diff --git a/gameforui.go b/gameforui.go
index ae642a4bd..99abfaa20 100644
--- a/gameforui.go
+++ b/gameforui.go
@@ -16,7 +16,6 @@ package ebiten
 
 import (
 	"fmt"
-	"sync"
 
 	"github.com/hajimehoshi/ebiten/v2/internal/graphicsdriver"
 )
@@ -25,16 +24,12 @@ type gameForUI struct {
 	game      Game
 	offscreen *Image
 	screen    *Image
-
-	m sync.Mutex
 }
 
-var theGameForUI = &gameForUI{}
-
-func (c *gameForUI) set(game Game) {
-	c.m.Lock()
-	defer c.m.Unlock()
-	c.game = game
+func newGameForUI(game Game) *gameForUI {
+	return &gameForUI{
+		game: game,
+	}
 }
 
 func (c *gameForUI) Layout(outsideWidth, outsideHeight float64, deviceScaleFactor float64) (int, int) {
diff --git a/run.go b/run.go
index d2eac1521..7de963b8f 100644
--- a/run.go
+++ b/run.go
@@ -150,10 +150,10 @@ func RunGame(game Game) error {
 	defer atomic.StoreInt32(&isRunGameEnded_, 1)
 
 	initializeWindowPositionIfNeeded(WindowSize())
-	theGameForUI.set(&imageDumperGame{
+	g := newGameForUI(&imageDumperGame{
 		game: game,
 	})
-	if err := ui.Get().Run(theGameForUI); err != nil {
+	if err := ui.Get().Run(g); err != nil {
 		if err == ui.RegularTermination {
 			return nil
 		}
diff --git a/run_mobile.go b/run_mobile.go
index 363a4b165..85c797518 100644
--- a/run_mobile.go
+++ b/run_mobile.go
@@ -27,8 +27,7 @@ import (
 // Ebiten users should NOT call RunGameWithoutMainLoop.
 // Instead, functions in github.com/hajimehoshi/ebiten/v2/mobile package calls this.
 //
-// TODO: Remove this. In order to remove this, the uiContext should be in another package.
+// TODO: Remove this. In order to remove this, the gameForUI should be in another package.
 func RunGameWithoutMainLoop(game Game) {
-	theGameForUI.set(game)
-	ui.Get().RunWithoutMainLoop(theGameForUI)
+	ui.Get().RunWithoutMainLoop(newGameForUI(game))
 }