diff --git a/src/game.cpp b/src/game.cpp
index 3c85c3e..32993c3 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -4,6 +4,8 @@
 #include "game.h"
 
 #include <KLocalizedString>
+#include <QCryptographicHash>
+#include <QJsonValue>
 #include <QLocale>
 #include <QUuid>
 
@@ -131,6 +133,58 @@ void Game::setWorkingDirectory(const QString &dir)
     }
 }
 
+QVariantMap Game::launchEnv() const
+{
+    return m_launchEnv;
+}
+
+void Game::setLaunchEnv(const QVariantMap &env)
+{
+    if (m_launchEnv != env) {
+        m_launchEnv = env;
+        Q_EMIT launchEnvChanged();
+    }
+}
+
+QString Game::launchRunner() const
+{
+    return m_launchRunner;
+}
+
+void Game::setLaunchRunner(const QString &runner)
+{
+    if (m_launchRunner != runner) {
+        m_launchRunner = runner;
+        Q_EMIT launchRunnerChanged();
+    }
+}
+
+QString Game::launchRunnerPath() const
+{
+    return m_launchRunnerPath;
+}
+
+void Game::setLaunchRunnerPath(const QString &path)
+{
+    if (m_launchRunnerPath != path) {
+        m_launchRunnerPath = path;
+        Q_EMIT launchRunnerPathChanged();
+    }
+}
+
+QString Game::launchPrefixPath() const
+{
+    return m_launchPrefixPath;
+}
+
+void Game::setLaunchPrefixPath(const QString &path)
+{
+    if (m_launchPrefixPath != path) {
+        m_launchPrefixPath = path;
+        Q_EMIT launchPrefixPathChanged();
+    }
+}
+
 QString Game::platform() const
 {
     return m_platform;
@@ -268,6 +322,32 @@ QJsonObject Game::toJson() const
     obj[QStringLiteral("favorite")] = m_favorite;
     obj[QStringLiteral("hidden")] = m_hidden;
     obj[QStringLiteral("installed")] = m_installed;
+
+    const bool hasLaunchConfig = !m_launchEnv.isEmpty() || !m_launchRunner.isEmpty() || !m_launchRunnerPath.isEmpty() || !m_launchPrefixPath.isEmpty();
+    if (hasLaunchConfig) {
+        QJsonObject launchObj;
+
+        if (!m_launchEnv.isEmpty()) {
+            QJsonObject envObj;
+            for (auto it = m_launchEnv.constBegin(); it != m_launchEnv.constEnd(); ++it) {
+                envObj.insert(it.key(), QJsonValue::fromVariant(it.value()));
+            }
+            launchObj.insert(QStringLiteral("env"), envObj);
+        }
+
+        if (!m_launchRunner.isEmpty()) {
+            launchObj.insert(QStringLiteral("runner"), m_launchRunner);
+        }
+        if (!m_launchRunnerPath.isEmpty()) {
+            launchObj.insert(QStringLiteral("runnerPath"), m_launchRunnerPath);
+        }
+        if (!m_launchPrefixPath.isEmpty()) {
+            launchObj.insert(QStringLiteral("prefixPath"), m_launchPrefixPath);
+        }
+
+        obj.insert(QStringLiteral("launch"), launchObj);
+    }
+
     return obj;
 }
 
@@ -276,26 +356,85 @@ Game *Game::fromJson(const QJsonObject &json, QObject *parent)
     QString id = json[QStringLiteral("id")].toString();
     QString name = json[QStringLiteral("name")].toString();
 
-    if (id.isEmpty() || name.isEmpty()) {
+    if (name.isEmpty()) {
         return nullptr;
     }
 
+    const QString platformId = json[QStringLiteral("platformId")].toString();
+    const QString platform = json[QStringLiteral("platform")].toString();
+    const QString launchCommand = json[QStringLiteral("launchCommand")].toString();
+    const QString workingDirectory = json[QStringLiteral("workingDirectory")].toString();
+    if (id.isEmpty()) {
+        const QByteArray fingerprint =
+            (platformId + QLatin1Char('|') + platform + QLatin1Char('|') + name + QLatin1Char('|') + launchCommand + QLatin1Char('|') + workingDirectory)
+                .toUtf8();
+        const QByteArray hash = QCryptographicHash::hash(fingerprint, QCryptographicHash::Sha1).toHex();
+        id = QStringLiteral("legacy-") + QString::fromLatin1(hash);
+    }
+
     Game *game = new Game(id, name, parent);
     game->setDescription(json[QStringLiteral("description")].toString());
     game->setDeveloper(json[QStringLiteral("developer")].toString());
     game->setPublisher(json[QStringLiteral("publisher")].toString());
     game->setCoverUrl(QUrl(json[QStringLiteral("coverUrl")].toString()));
     game->setIconUrl(QUrl(json[QStringLiteral("iconUrl")].toString()));
-    game->setLaunchCommand(json[QStringLiteral("launchCommand")].toString());
-    game->setWorkingDirectory(json[QStringLiteral("workingDirectory")].toString());
-    game->setPlatform(json[QStringLiteral("platform")].toString());
-    game->setPlatformId(json[QStringLiteral("platformId")].toString());
+    game->setLaunchCommand(launchCommand);
+    game->setWorkingDirectory(workingDirectory);
+    game->setPlatform(platform);
+    game->setPlatformId(platformId);
     game->setDateAdded(QDateTime::fromString(json[QStringLiteral("dateAdded")].toString(), Qt::ISODate));
     game->setLastPlayed(QDateTime::fromString(json[QStringLiteral("lastPlayed")].toString(), Qt::ISODate));
     game->setPlayTime(json[QStringLiteral("playTime")].toInteger());
     game->setFavorite(json[QStringLiteral("favorite")].toBool());
     game->setHidden(json[QStringLiteral("hidden")].toBool());
     game->setInstalled(json[QStringLiteral("installed")].toBool(true));
+
+    QVariantMap env;
+    QString runner;
+    QString runnerPath;
+    QString prefixPath;
+    const QJsonValue launchValue = json.value(QStringLiteral("launch"));
+    if (launchValue.isObject()) {
+        const QJsonObject launchObj = launchValue.toObject();
+        const QJsonValue envValue = launchObj.value(QStringLiteral("env"));
+        if (envValue.isObject()) {
+            env = envValue.toObject().toVariantMap();
+        }
+
+        runner = launchObj.value(QStringLiteral("runner")).toString();
+        runnerPath = launchObj.value(QStringLiteral("runnerPath")).toString();
+        prefixPath = launchObj.value(QStringLiteral("prefixPath")).toString();
+    }
+
+    const QJsonValue legacyEnvValue = json.value(QStringLiteral("launchEnv"));
+    if (env.isEmpty() && legacyEnvValue.isObject()) {
+        env = legacyEnvValue.toObject().toVariantMap();
+    }
+
+    if (runner.isEmpty()) {
+        runner = json.value(QStringLiteral("launchRunner")).toString();
+    }
+    if (runnerPath.isEmpty()) {
+        runnerPath = json.value(QStringLiteral("launchRunnerPath")).toString();
+    }
+    if (prefixPath.isEmpty()) {
+        prefixPath = json.value(QStringLiteral("launchPrefixPath")).toString();
+    }
+
+    if (!env.isEmpty()) {
+        game->setLaunchEnv(env);
+    }
+
+    if (!runner.isEmpty()) {
+        game->setLaunchRunner(runner);
+    }
+    if (!runnerPath.isEmpty()) {
+        game->setLaunchRunnerPath(runnerPath);
+    }
+    if (!prefixPath.isEmpty()) {
+        game->setLaunchPrefixPath(prefixPath);
+    }
+
     return game;
 }
 
diff --git a/src/game.h b/src/game.h
index eed97c5..05304b8 100644
--- a/src/game.h
+++ b/src/game.h
@@ -9,6 +9,7 @@
 #include <QQmlEngine>
 #include <QString>
 #include <QUrl>
+#include <QVariantMap>
 
 class Game : public QObject
 {
@@ -25,6 +26,10 @@ class Game : public QObject
     Q_PROPERTY(QUrl iconUrl READ iconUrl WRITE setIconUrl NOTIFY iconUrlChanged)
     Q_PROPERTY(QString launchCommand READ launchCommand WRITE setLaunchCommand NOTIFY launchCommandChanged)
     Q_PROPERTY(QString workingDirectory READ workingDirectory WRITE setWorkingDirectory NOTIFY workingDirectoryChanged)
+    Q_PROPERTY(QVariantMap launchEnv READ launchEnv WRITE setLaunchEnv NOTIFY launchEnvChanged)
+    Q_PROPERTY(QString launchRunner READ launchRunner WRITE setLaunchRunner NOTIFY launchRunnerChanged)
+    Q_PROPERTY(QString launchRunnerPath READ launchRunnerPath WRITE setLaunchRunnerPath NOTIFY launchRunnerPathChanged)
+    Q_PROPERTY(QString launchPrefixPath READ launchPrefixPath WRITE setLaunchPrefixPath NOTIFY launchPrefixPathChanged)
     Q_PROPERTY(QString platform READ platform WRITE setPlatform NOTIFY platformChanged)
     Q_PROPERTY(QString platformId READ platformId WRITE setPlatformId NOTIFY platformIdChanged)
     Q_PROPERTY(QDateTime dateAdded READ dateAdded WRITE setDateAdded NOTIFY dateAddedChanged)
@@ -65,6 +70,18 @@ public:
     QString workingDirectory() const;
     void setWorkingDirectory(const QString &dir);
 
+    QVariantMap launchEnv() const;
+    void setLaunchEnv(const QVariantMap &env);
+
+    QString launchRunner() const;
+    void setLaunchRunner(const QString &runner);
+
+    QString launchRunnerPath() const;
+    void setLaunchRunnerPath(const QString &path);
+
+    QString launchPrefixPath() const;
+    void setLaunchPrefixPath(const QString &path);
+
     QString platform() const;
     void setPlatform(const QString &platform);
 
@@ -108,6 +125,10 @@ Q_SIGNALS:
     void iconUrlChanged();
     void launchCommandChanged();
     void workingDirectoryChanged();
+    void launchEnvChanged();
+    void launchRunnerChanged();
+    void launchRunnerPathChanged();
+    void launchPrefixPathChanged();
     void platformChanged();
     void platformIdChanged();
     void dateAddedChanged();
@@ -128,6 +149,10 @@ private:
     QUrl m_iconUrl;
     QString m_launchCommand;
     QString m_workingDirectory;
+    QVariantMap m_launchEnv;
+    QString m_launchRunner;
+    QString m_launchRunnerPath;
+    QString m_launchPrefixPath;
     QString m_platform;
     QString m_platformId;
     QDateTime m_dateAdded;
diff --git a/src/gamelauncher.cpp b/src/gamelauncher.cpp
index a653f81..8afe8e6 100644
--- a/src/gamelauncher.cpp
+++ b/src/gamelauncher.cpp
@@ -7,9 +7,107 @@
 #include <QCoreApplication>
 #include <QDateTime>
 #include <QDesktopServices>
+#include <QDir>
+#include <QFileInfo>
+#include <QProcessEnvironment>
+#include <QStandardPaths>
 #include <QTimer>
 #include <QUrl>
 
+static QStringList steamCandidateRoots()
+{
+    const QString home = QDir::homePath();
+    return {
+        home + QStringLiteral("/.steam/root"),
+        home + QStringLiteral("/.steam/steam"),
+        home + QStringLiteral("/.local/share/Steam"),
+        home + QStringLiteral("/.var/app/com.valvesoftware.Steam/data/Steam"),
+        home + QStringLiteral("/.var/app/com.valvesoftware.Steam/.local/share/Steam"),
+    };
+}
+
+static QString findSteamClientInstallPathFromProton(const QString &protonExe)
+{
+    if (protonExe.isEmpty()) {
+        return {};
+    }
+
+    QDir dir(QFileInfo(protonExe).absoluteDir());
+    for (int i = 0; i < 10; ++i) {
+        if (dir.exists(QStringLiteral("steamapps"))) {
+            return dir.absolutePath();
+        }
+        if (!dir.cdUp()) {
+            break;
+        }
+    }
+
+    for (const QString &root : steamCandidateRoots()) {
+        if (QDir(root).exists(QStringLiteral("steamapps"))) {
+            return root;
+        }
+    }
+
+    return {};
+}
+
+static QString discoverDefaultProtonExecutable()
+{
+    static bool done = false;
+    static QString cached;
+
+    if (done) {
+        return cached;
+    }
+    done = true;
+
+    QStringList candidates;
+    for (const QString &root : steamCandidateRoots()) {
+        const QString compatTools = root + QStringLiteral("/compatibilitytools.d");
+        QDir compatDir(compatTools);
+        if (compatDir.exists()) {
+            const QStringList toolDirs = compatDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);
+            for (const QString &tool : toolDirs) {
+                const QString protonPath = compatTools + QLatin1Char('/') + tool + QStringLiteral("/proton");
+                if (QFileInfo::exists(protonPath)) {
+                    candidates.append(protonPath);
+                }
+            }
+        }
+
+        const QString common = root + QStringLiteral("/steamapps/common");
+        QDir commonDir(common);
+        if (commonDir.exists()) {
+            const QStringList dirs = commonDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);
+            for (const QString &d : dirs) {
+                if (!d.contains(QStringLiteral("Proton"), Qt::CaseInsensitive)) {
+                    continue;
+                }
+                const QString protonPath = common + QLatin1Char('/') + d + QStringLiteral("/proton");
+                if (QFileInfo::exists(protonPath)) {
+                    candidates.append(protonPath);
+                }
+            }
+        }
+    }
+
+    candidates.removeDuplicates();
+    candidates.sort();
+
+    for (const QString &c : candidates) {
+        if (c.contains(QStringLiteral("Proton - Experimental"))) {
+            cached = c;
+            return cached;
+        }
+    }
+
+    if (!candidates.isEmpty()) {
+        cached = candidates.constLast();
+    }
+
+    return cached;
+}
+
 GameLauncher::GameLauncher(QObject *parent)
     : QObject(parent)
 {
@@ -46,6 +144,12 @@ void GameLauncher::launchGame(Game *game)
         return;
     }
 
+    const QString runner = game->launchRunner().trimmed();
+    const QString runnerPath = game->launchRunnerPath().trimmed();
+    const QString prefixPath = game->launchPrefixPath().trimmed();
+    const QVariantMap launchEnv = game->launchEnv();
+    const bool hasLaunchOverrides = !runner.isEmpty() || !runnerPath.isEmpty() || !prefixPath.isEmpty() || !launchEnv.isEmpty();
+
     // Check if already running
     if (m_runningGames.contains(game->id())) {
         Q_EMIT gameError(game, tr("Game is already running"));
@@ -53,7 +157,7 @@ void GameLauncher::launchGame(Game *game)
     }
 
     // Handle Steam URLs
-    if (command.startsWith(QLatin1String("steam://"))) {
+    if (!hasLaunchOverrides && command.startsWith(QLatin1String("steam://"))) {
         QDesktopServices::openUrl(QUrl(command));
         game->setLastPlayed(QDateTime::currentDateTime());
         Q_EMIT gameStarted(game);
@@ -61,7 +165,7 @@ void GameLauncher::launchGame(Game *game)
     }
 
     // Handle Lutris URLs
-    if (command.startsWith(QLatin1String("lutris "))) {
+    if (!hasLaunchOverrides && command.startsWith(QLatin1String("lutris "))) {
         QString lutrisCommand = command.mid(7); // Remove "lutris "
         QDesktopServices::openUrl(QUrl(lutrisCommand));
         game->setLastPlayed(QDateTime::currentDateTime());
@@ -72,6 +176,21 @@ void GameLauncher::launchGame(Game *game)
     // Start process for other commands
     QProcess *process = new QProcess(this);
 
+    // Apply per-game environment variables
+    QProcessEnvironment env;
+    bool envChanged = false;
+    if (!launchEnv.isEmpty()) {
+        env = QProcessEnvironment::systemEnvironment();
+        envChanged = true;
+        for (auto it = launchEnv.constBegin(); it != launchEnv.constEnd(); ++it) {
+            const QString key = it.key();
+            if (key.isEmpty() || key.contains(QLatin1Char('='))) {
+                continue;
+            }
+            env.insert(key, it.value().toString());
+        }
+    }
+
     // Set working directory if available
     if (!game->workingDirectory().isEmpty()) {
         process->setWorkingDirectory(game->workingDirectory());
@@ -84,7 +203,14 @@ void GameLauncher::launchGame(Game *game)
     m_processToGame.insert(process, game);
 
     // Parse command and arguments
-    QStringList parts = QProcess::splitCommand(command);
+    QStringList parts;
+    if (command.startsWith(QLatin1String("steam://"))) {
+        parts = {QStringLiteral("xdg-open"), command};
+    } else if (command.startsWith(QLatin1String("lutris "))) {
+        parts = {QStringLiteral("xdg-open"), command.mid(7)};
+    } else {
+        parts = QProcess::splitCommand(command);
+    }
     if (parts.isEmpty()) {
         cleanupProcess(process);
         Q_EMIT gameError(game, tr("Invalid launch command"));
@@ -92,7 +218,89 @@ void GameLauncher::launchGame(Game *game)
     }
 
     QString program = parts.takeFirst();
-    process->start(program, parts);
+
+    QString finalProgram = program;
+    QStringList finalArgs = parts;
+
+    if ((runner == QLatin1String("wine") || runner == QLatin1String("proton")) && (program == QLatin1String("xdg-open"))) {
+        cleanupProcess(process);
+        Q_EMIT gameError(game, tr("This runner cannot be used with URL-based launch commands"));
+        return;
+    }
+
+    if (runner == QLatin1String("custom")) {
+        if (runnerPath.isEmpty()) {
+            cleanupProcess(process);
+            Q_EMIT gameError(game, tr("Custom runner is enabled but no runner path is configured"));
+            return;
+        }
+        finalProgram = runnerPath;
+        finalArgs = {program};
+        finalArgs.append(parts);
+    } else if (runner == QLatin1String("wine")) {
+        QString wineExe = runnerPath;
+        if (wineExe.isEmpty()) {
+            wineExe = QStandardPaths::findExecutable(QStringLiteral("wine"));
+        }
+        if (wineExe.isEmpty()) {
+            cleanupProcess(process);
+            Q_EMIT gameError(game, tr("Wine runner is enabled but Wine was not found"));
+            return;
+        }
+
+        QString winePrefix = prefixPath;
+        if (winePrefix.isEmpty()) {
+            winePrefix = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation) + QStringLiteral("/prefixes/") + game->id();
+        }
+        QDir().mkpath(winePrefix);
+
+        if (!envChanged) {
+            env = QProcessEnvironment::systemEnvironment();
+            envChanged = true;
+        }
+        env.insert(QStringLiteral("WINEPREFIX"), winePrefix);
+
+        finalProgram = wineExe;
+        finalArgs = {program};
+        finalArgs.append(parts);
+    } else if (runner == QLatin1String("proton")) {
+        QString protonExe = runnerPath;
+        if (protonExe.isEmpty()) {
+            protonExe = discoverDefaultProtonExecutable();
+        }
+        if (protonExe.isEmpty()) {
+            cleanupProcess(process);
+            Q_EMIT gameError(game, tr("Proton runner is enabled but no Proton installation was found"));
+            return;
+        }
+
+        QString steamInstallPath = findSteamClientInstallPathFromProton(protonExe);
+
+        QString compatDataPath = prefixPath;
+        if (compatDataPath.isEmpty()) {
+            compatDataPath = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation) + QStringLiteral("/prefixes/") + game->id();
+        }
+        QDir().mkpath(compatDataPath);
+
+        if (!envChanged) {
+            env = QProcessEnvironment::systemEnvironment();
+            envChanged = true;
+        }
+        env.insert(QStringLiteral("STEAM_COMPAT_DATA_PATH"), compatDataPath);
+        if (!steamInstallPath.isEmpty()) {
+            env.insert(QStringLiteral("STEAM_COMPAT_CLIENT_INSTALL_PATH"), steamInstallPath);
+        }
+
+        finalProgram = protonExe;
+        finalArgs = {QStringLiteral("run"), program};
+        finalArgs.append(parts);
+    }
+
+    if (envChanged) {
+        process->setProcessEnvironment(env);
+    }
+
+    process->start(finalProgram, finalArgs);
 
     if (!process->waitForStarted(5000)) {
         QString error = process->errorString();
diff --git a/src/qml/GameEditDialog.qml b/src/qml/GameEditDialog.qml
index 19ee729..ebf6090 100644
--- a/src/qml/GameEditDialog.qml
+++ b/src/qml/GameEditDialog.qml
@@ -15,6 +15,10 @@ Kirigami.Dialog {
     property var game: null
     property bool isEditing: game !== null
 
+    ListModel {
+        id: envModel
+    }
+
     signal gameCreated(var game)
     signal gameUpdated(var game)
 
@@ -31,13 +35,24 @@ Kirigami.Dialog {
         Kirigami.Action {
             text: isEditing ? i18n("Apply") : i18n("Add")
             icon.name: isEditing ? "dialog-ok-apply" : "list-add"
-            enabled: nameField.text.trim() !== "" && executableField.text.trim() !== ""
+            enabled: nameField.text.trim() !== "" && executableField.text.trim() !== "" && (runnerCombo.currentIndex !== 3 || runnerPathField.text.trim() !== "")
             onTriggered: {
+                let runnerValue = dialog.runnerFromIndex(runnerCombo.currentIndex)
+                let runnerPathValue = runnerPathField.text.trim()
+                let prefixPathValue = prefixPathField.text.trim()
+                if (runnerValue === "") {
+                    runnerPathValue = ""
+                    prefixPathValue = ""
+                }
                 if (isEditing) {
                     game.name = nameField.text.trim()
                     game.developer = developerField.text.trim()
                     game.launchCommand = executableField.text.trim()
                     game.workingDirectory = workingDirField.text.trim()
+                    game.launchEnv = dialog.envModelToMap()
+                    game.launchRunner = runnerValue
+                    game.launchRunnerPath = runnerPathValue
+                    game.launchPrefixPath = prefixPathValue
                     if (selectedCoverPath !== "") {
                         App.setCoverFromFile(game, selectedCoverPath)
                     }
@@ -48,6 +63,10 @@ Kirigami.Dialog {
                     if (newGame) {
                         newGame.developer = developerField.text.trim()
                         newGame.workingDirectory = workingDirField.text.trim()
+                        newGame.launchEnv = dialog.envModelToMap()
+                        newGame.launchRunner = runnerValue
+                        newGame.launchRunnerPath = runnerPathValue
+                        newGame.launchPrefixPath = prefixPathValue
                         if (selectedCoverPath !== "") {
                             App.setCoverFromFile(newGame, selectedCoverPath)
                         }
@@ -109,18 +128,75 @@ Kirigami.Dialog {
         }
     }
 
+    function envModelToMap() {
+        let result = ({})
+        for (let i = 0; i < envModel.count; i++) {
+            let row = envModel.get(i)
+            let k = (row.key || "").trim()
+            if (k === "") continue
+            if (k.indexOf("=") !== -1) continue
+            result[k] = String(row.value || "")
+        }
+        return result
+    }
+
+    function setEnvVar(key, value) {
+        let k = (key || "").trim()
+        if (k === "") return
+        for (let i = 0; i < envModel.count; i++) {
+            let row = envModel.get(i)
+            if ((row.key || "").trim() === k) {
+                envModel.setProperty(i, "value", String(value || ""))
+                return
+            }
+        }
+        envModel.append({ key: k, value: String(value || "") })
+    }
+
+    function runnerFromIndex(idx) {
+        if (idx === 1) return "wine"
+        if (idx === 2) return "proton"
+        if (idx === 3) return "custom"
+        return ""
+    }
+
+    function runnerToIndex(runner) {
+        let r = (runner || "").trim().toLowerCase()
+        if (r === "wine") return 1
+        if (r === "proton") return 2
+        if (r === "custom") return 3
+        return 0
+    }
+
     function loadFields() {
         selectedCoverPath = ""
+        envModel.clear()
         if (isEditing && game) {
             nameField.text = game.name || ""
             developerField.text = game.developer || ""
             executableField.text = game.launchCommand || ""
             workingDirField.text = game.workingDirectory || ""
+
+            runnerCombo.currentIndex = dialog.runnerToIndex(game.launchRunner)
+            runnerPathField.text = game.launchRunnerPath || ""
+            prefixPathField.text = game.launchPrefixPath || ""
+
+            let env = game.launchEnv || ({})
+            let keys = Object.keys(env)
+            keys.sort()
+            for (let i = 0; i < keys.length; i++) {
+                let k = keys[i]
+                envModel.append({ key: k, value: String(env[k]) })
+            }
         } else {
             nameField.text = ""
             developerField.text = ""
             executableField.text = ""
             workingDirField.text = ""
+
+            runnerCombo.currentIndex = 0
+            runnerPathField.text = ""
+            prefixPathField.text = ""
         }
     }
 
@@ -215,6 +291,168 @@ Kirigami.Dialog {
                 text: ""
                 placeholderText: i18n("Optional")
             }
+
+            FormCard.FormDelegateSeparator {}
+
+            FormCard.FormCard {
+                Layout.fillWidth: true
+                Layout.topMargin: Kirigami.Units.largeSpacing
+
+                FormCard.FormHeader {
+                    title: i18n("Compatibility")
+                }
+
+                Item {
+                    Layout.fillWidth: true
+                    Layout.margins: Kirigami.Units.largeSpacing
+
+                    RowLayout {
+                        anchors.left: parent.left
+                        anchors.right: parent.right
+                        spacing: Kirigami.Units.largeSpacing
+
+                        QQC2.Label {
+                            text: i18n("Runner")
+                            Layout.alignment: Qt.AlignVCenter
+                        }
+
+                        QQC2.ComboBox {
+                            id: runnerCombo
+                            Layout.fillWidth: true
+                            model: [i18n("Native"), i18n("Wine"), i18n("Proton"), i18n("Custom")]
+                        }
+                    }
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormTextFieldDelegate {
+                    id: runnerPathField
+                    label: i18n("Runner Path")
+                    text: ""
+                    placeholderText: runnerCombo.currentIndex === 2 ? i18n("Auto-detect Proton") : (runnerCombo.currentIndex === 1 ? i18n("Use system Wine") : i18n("Required for Custom"))
+                    enabled: runnerCombo.currentIndex !== 0
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormButtonDelegate {
+                    text: i18n("Browse Runner...")
+                    icon.name: "document-open"
+                    enabled: runnerCombo.currentIndex !== 0
+                    onClicked: runnerFileDialog.open()
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormTextFieldDelegate {
+                    id: prefixPathField
+                    label: i18n("Prefix Path")
+                    text: ""
+                    placeholderText: i18n("Default (AppDataLocation/prefixes/<gameId>)")
+                    enabled: runnerCombo.currentIndex === 1 || runnerCombo.currentIndex === 2
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormButtonDelegate {
+                    text: i18n("Browse Prefix...")
+                    icon.name: "document-open-folder"
+                    enabled: runnerCombo.currentIndex === 1 || runnerCombo.currentIndex === 2
+                    onClicked: prefixFolderDialog.open()
+                }
+            }
+
+            FormCard.FormCard {
+                Layout.fillWidth: true
+                Layout.topMargin: Kirigami.Units.largeSpacing
+
+                FormCard.FormHeader {
+                    title: i18n("Environment Variables")
+                }
+
+                FormCard.FormTextDelegate {
+                    text: i18n("These variables are applied only when launching this game from A-La-Karte.")
+                    textItem.wrapMode: Text.WordWrap
+                    textItem.font: Kirigami.Theme.smallFont
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormButtonDelegate {
+                    text: i18n("Add Variable")
+                    icon.name: "list-add"
+                    onClicked: envModel.append({ key: "", value: "" })
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormButtonDelegate {
+                    text: i18n("Preset: MangoHud")
+                    description: i18n("Sets MANGOHUD=1")
+                    icon.name: "games-hint"
+                    onClicked: dialog.setEnvVar("MANGOHUD", "1")
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormButtonDelegate {
+                    text: i18n("Preset: GameMode")
+                    description: i18n("Sets GAMEMODERUN=1")
+                    icon.name: "speedometer"
+                    onClicked: dialog.setEnvVar("GAMEMODERUN", "1")
+                }
+
+                FormCard.FormDelegateSeparator {}
+
+                FormCard.FormButtonDelegate {
+                    text: i18n("Clear Variables")
+                    icon.name: "edit-clear"
+                    enabled: envModel.count > 0
+                    onClicked: envModel.clear()
+                }
+
+                Item {
+                    Layout.fillWidth: true
+                    Layout.margins: Kirigami.Units.largeSpacing
+
+                    ColumnLayout {
+                        anchors.left: parent.left
+                        anchors.right: parent.right
+                        spacing: Kirigami.Units.smallSpacing
+
+                        Repeater {
+                            model: envModel
+
+                            RowLayout {
+                                Layout.fillWidth: true
+                                spacing: Kirigami.Units.smallSpacing
+
+                                QQC2.TextField {
+                                    Layout.fillWidth: true
+                                    Layout.preferredWidth: 1
+                                    placeholderText: i18n("KEY")
+                                    text: key
+                                    onTextChanged: envModel.setProperty(index, "key", text)
+                                }
+
+                                QQC2.TextField {
+                                    Layout.fillWidth: true
+                                    Layout.preferredWidth: 2
+                                    placeholderText: i18n("VALUE")
+                                    text: value
+                                    onTextChanged: envModel.setProperty(index, "value", text)
+                                }
+
+                                QQC2.ToolButton {
+                                    icon.name: "list-remove"
+                                    onClicked: envModel.remove(index)
+                                }
+                            }
+                        }
+                    }
+                }
+            }
         }
 
         FormCard.FormCard {
@@ -339,6 +577,23 @@ Kirigami.Dialog {
         }
     }
 
+    FileDialog {
+        id: runnerFileDialog
+        title: i18n("Select Runner Executable")
+        fileMode: FileDialog.OpenFile
+        onAccepted: {
+            runnerPathField.text = selectedFile.toString().replace("file://", "")
+        }
+    }
+
+    FolderDialog {
+        id: prefixFolderDialog
+        title: i18n("Select Prefix Folder")
+        onAccepted: {
+            prefixPathField.text = selectedFolder.toString().replace("file://", "")
+        }
+    }
+
     function saveCoverImage(game) {
         if (selectedCoverPath === "") return