diff --git a/babylonia-terminal-gui/src/lib.rs b/babylonia-terminal-gui/src/lib.rs
index cdd834c..e076d8b 100644
--- a/babylonia-terminal-gui/src/lib.rs
+++ b/babylonia-terminal-gui/src/lib.rs
@@ -1,112 +1,11 @@
-use babylonia_terminal_sdk::game_state::GameState;
 use log::debug;
-use manager::run_game;
-use relm4::{
-    gtk::{
-        self,
-        prelude::{BoxExt, ButtonExt, GtkWindowExt, OrientableExt, WidgetExt},
-    },
-    loading_widgets::LoadingWidgets,
-    prelude::{AsyncComponent, AsyncComponentParts, SimpleAsyncComponent},
-    view, ComponentParts, RelmWidgetExt, SimpleComponent,
-};
-use relm4::{Component, RelmApp};
+use relm4::RelmApp;
 
 mod manager;
+mod ui;
 
 pub fn run() {
     debug!("Start GUI!");
     let app = RelmApp::new("moe.celica.BabyloniaTerminal").with_args(vec![]);
-    app.run_async::<MainWindow>(None);
-}
-
-#[derive(Debug)]
-pub enum MainWindowMsg {
-    RunGame,
-}
-
-struct MainWindow {
-    game_state: GameState,
-    is_game_running: bool,
-}
-
-impl MainWindow {
-    fn new(game_state: GameState) -> Self {
-        MainWindow {
-            game_state,
-            is_game_running: false,
-        }
-    }
-}
-
-#[relm4::component(async)]
-impl SimpleAsyncComponent for MainWindow {
-    type Input = MainWindowMsg;
-
-    type Output = ();
-
-    type Init = Option<GameState>;
-
-    view! {
-        #[root]
-        gtk::Window {
-            gtk::Box {
-                set_orientation: gtk::Orientation::Vertical,
-                set_spacing: 5,
-                set_margin_all: 5,
-
-                #[name(start_button)]
-                gtk::Button {
-                    set_label: "Start game",
-                    connect_clicked => MainWindowMsg::RunGame,
-                },
-            }
-        }
-    }
-
-    async fn init(
-        game_state: Self::Init,
-        root: Self::Root,
-        sender: relm4::AsyncComponentSender<Self>,
-    ) -> AsyncComponentParts<Self> {
-        let model;
-        if game_state.is_none() {
-            model = MainWindow::new(
-                babylonia_terminal_sdk::game_state::GameState::get_current_state()
-                    .await
-                    .unwrap(),
-            );
-        } else {
-            model = MainWindow::new(game_state.unwrap());
-        }
-
-        let widgets = view_output!();
-
-        AsyncComponentParts { model, widgets }
-    }
-
-    fn init_loading_widgets(root: Self::Root) -> Option<LoadingWidgets> {
-        view! {
-            #[local]
-            root {
-                set_title: Some("Babylonia Terminal"),
-                set_default_width: 700,
-                set_default_height: 300,
-
-                #[name(spinner)]
-                gtk::Spinner {
-                    start: (),
-                    set_halign: gtk::Align::Center,
-                }
-            }
-        }
-
-        Some(LoadingWidgets::new(root, spinner))
-    }
-
-    async fn update(&mut self, message: Self::Input, _sender: relm4::AsyncComponentSender<Self>) {
-        match message {
-            MainWindowMsg::RunGame => run_game().await,
-        }
-    }
+    ui::run(app);
 }
diff --git a/babylonia-terminal-gui/src/manager.rs b/babylonia-terminal-gui/src/manager.rs
index 63c8495..f19e818 100644
--- a/babylonia-terminal-gui/src/manager.rs
+++ b/babylonia-terminal-gui/src/manager.rs
@@ -3,9 +3,14 @@ use babylonia_terminal_sdk::{
     game_manager::GameManager,
 };
 use log::error;
-use relm4::tokio::sync::OnceCell;
+use relm4::{
+    tokio::{self, sync::OnceCell},
+    Worker,
+};
 use wincompatlib::prelude::Proton;
 
+use crate::ui;
+
 static PROTON: OnceCell<Proton> = OnceCell::const_new();
 
 pub async fn get_proton() -> Proton {
@@ -31,3 +36,38 @@ pub async fn run_game() {
 
     GameManager::start_game(&proton, game_dir.unwrap(), None, false).await;
 }
+
+#[derive(Debug)]
+pub enum HandleGameProcessMsg {
+    RunGame,
+}
+
+pub struct HandleGameProcess;
+
+impl Worker for HandleGameProcess {
+    type Init = ();
+
+    type Input = HandleGameProcessMsg;
+
+    type Output = ui::MainWindowMsg;
+
+    fn init(_init: Self::Init, _sender: relm4::ComponentSender<Self>) -> Self {
+        Self
+    }
+
+    fn update(&mut self, message: Self::Input, sender: relm4::ComponentSender<Self>) {
+        match message {
+            HandleGameProcessMsg::RunGame => {
+                tokio::runtime::Builder::new_current_thread()
+                    .enable_all()
+                    .build()
+                    .unwrap()
+                    .block_on(async {
+                        sender.output(ui::MainWindowMsg::SetIsGameRunning(true));
+                        run_game().await;
+                        sender.output(ui::MainWindowMsg::SetIsGameRunning(false));
+                    });
+            }
+        }
+    }
+}
diff --git a/babylonia-terminal-gui/src/ui/mod.rs b/babylonia-terminal-gui/src/ui/mod.rs
new file mode 100644
index 0000000..843acb5
--- /dev/null
+++ b/babylonia-terminal-gui/src/ui/mod.rs
@@ -0,0 +1,118 @@
+use std::convert::identity;
+
+use crate::manager;
+use babylonia_terminal_sdk::game_state::GameState;
+
+use relm4::{
+    gtk::{
+        self,
+        prelude::{BoxExt, ButtonExt, GtkWindowExt, OrientableExt, WidgetExt},
+    },
+    loading_widgets::LoadingWidgets,
+    prelude::{AsyncComponentParts, SimpleAsyncComponent},
+    view, Component, RelmApp, RelmWidgetExt, WorkerController,
+};
+
+pub fn run(app: RelmApp<MainWindowMsg>) {
+    app.run_async::<MainWindow>(None);
+}
+
+#[derive(Debug)]
+pub enum MainWindowMsg {
+    SetIsGameRunning(bool),
+}
+
+struct MainWindow {
+    game_handler: WorkerController<manager::HandleGameProcess>,
+    game_state: GameState,
+    is_game_running: bool,
+}
+
+impl MainWindow {
+    fn new(game_state: GameState, sender: relm4::AsyncComponentSender<Self>) -> Self {
+        MainWindow {
+            game_state,
+            is_game_running: false,
+            game_handler: manager::HandleGameProcess::builder()
+                .detach_worker(())
+                .forward(sender.input_sender(), identity),
+        }
+    }
+}
+
+#[relm4::component(async)]
+impl SimpleAsyncComponent for MainWindow {
+    type Input = MainWindowMsg;
+
+    type Output = ();
+
+    type Init = Option<GameState>;
+
+    view! {
+        #[root]
+        gtk::Window {
+            gtk::Box {
+                set_orientation: gtk::Orientation::Vertical,
+                set_spacing: 5,
+                set_margin_all: 5,
+
+                #[name(start_button)]
+                gtk::Button {
+                    #[watch]
+                    set_sensitive: !model.is_game_running,
+                    set_label: "Start game",
+                    connect_clicked[sender = model.game_handler.sender().clone()] => move |_| {
+                        sender.send(manager::HandleGameProcessMsg::RunGame).unwrap();
+                    },
+                },
+            }
+        }
+    }
+
+    async fn init(
+        game_state: Self::Init,
+        root: Self::Root,
+        sender: relm4::AsyncComponentSender<Self>,
+    ) -> AsyncComponentParts<Self> {
+        let model;
+        if game_state.is_none() {
+            model = MainWindow::new(
+                babylonia_terminal_sdk::game_state::GameState::get_current_state()
+                    .await
+                    .unwrap(),
+                sender,
+            );
+        } else {
+            model = MainWindow::new(game_state.unwrap(), sender);
+        }
+
+        let widgets = view_output!();
+
+        AsyncComponentParts { model, widgets }
+    }
+
+    fn init_loading_widgets(root: Self::Root) -> Option<LoadingWidgets> {
+        view! {
+            #[local]
+            root {
+                set_title: Some("Babylonia Terminal"),
+                set_default_width: 700,
+                set_default_height: 300,
+
+                #[name(spinner)]
+                gtk::Spinner {
+                    start: (),
+                    set_halign: gtk::Align::Center,
+                }
+            }
+        }
+
+        Some(LoadingWidgets::new(root, spinner))
+    }
+
+    async fn update(&mut self, message: Self::Input, _sender: relm4::AsyncComponentSender<Self>) {
+        match message {
+            MainWindowMsg::SetIsGameRunning(value) => self.is_game_running = value,
+        }
+    }
+}