diff --git a/src/NewGamePanel.gd b/src/NewGamePanel.gd
index 14d8979..2a68715 100644
--- a/src/NewGamePanel.gd
+++ b/src/NewGamePanel.gd
@@ -44,6 +44,7 @@ func _on_NewGamePanel_about_to_show():
 		"hard":
 			$Panel/HBoxContainer/Hard.pressed = true
 		_:
+			assert("Invalid value")
 			$Panel/HBoxContainer/Normal.pressed = true
 
 	$Panel/Start.grab_focus()
diff --git a/src/Taquin.gd b/src/Taquin.gd
index abbb580..b365d44 100644
--- a/src/Taquin.gd
+++ b/src/Taquin.gd
@@ -81,8 +81,7 @@ func _ready() -> void:
 	var hidden_piece = rows * columns # Last piece is hidden
 	
 	init(pieces_order, hidden_piece)
-
-	shuffle(difficulty)
+	shuffle(difficulty, 0.0)
 
 func _input(event):
 	if $AnimationPlayer.is_playing():
@@ -101,13 +100,13 @@ func _input(event):
 	# Handle keyboard input
 	#
 	if event.is_action_pressed("ui_up"):
-		move_piece(Direction.UP)
+		move_piece(Direction.UP, 1.0)
 	if event.is_action_pressed("ui_down"):
-		move_piece(Direction.DOWN)
+		move_piece(Direction.DOWN, 1.0)
 	if event.is_action_pressed("ui_left"):
-		move_piece(Direction.LEFT)
+		move_piece(Direction.LEFT, 1.0)
 	if event.is_action_pressed("ui_right"):
-		move_piece(Direction.RIGHT)
+		move_piece(Direction.RIGHT, 1.0)
 
 	#
 	# Handle touch input
@@ -144,7 +143,7 @@ func _input(event):
 				var current_position = current_sliding_piece.position
 				if current_position.distance_to(current_origin) > current_position.distance_to(current_goal):
 					current_sliding_piece.position = current_goal
-					commit_slide()
+					commit_slide(true)
 				else:
 					reset_position(current_sliding_piece)
 					reset_slide()
@@ -210,30 +209,35 @@ func sliding_piece_for_direction(direction) -> Piece:
 	
 	return piece
 
-func move_piece(direction) -> void:
+func move_piece(direction, speed: float) -> void:
 	current_sliding_piece = sliding_piece_for_direction(direction)
 	if current_sliding_piece == null:
 		reset_slide()
 		return
 
-	var moving_piece_animation: Animation = $AnimationPlayer.get_animation("MovingPiece")
-
-	assert(moving_piece_animation != null)
-	assert(moving_piece_animation.get_track_count() > 0)
-
-	var moving_piece_track_index: int = moving_piece_animation.find_track(current_animation_path)
-
-	assert(moving_piece_track_index != -1)
-
-	var new_animation_path: String = str($AnimationPlayer.get_parent().get_path_to(current_sliding_piece), ":position")
-	moving_piece_animation.track_set_path(moving_piece_track_index, new_animation_path)
-	current_animation_path = new_animation_path
+	if speed > 0.0:
+		var moving_piece_animation: Animation = $AnimationPlayer.get_animation("MovingPiece")
 	
-	moving_piece_animation.track_set_key_value(moving_piece_track_index, 0, current_sliding_piece.position)
-	moving_piece_animation.track_set_key_value(moving_piece_track_index, 1, missing_piece.position)
-	$AnimationPlayer.play("MovingPiece")
+		assert(moving_piece_animation != null)
+		assert(moving_piece_animation.get_track_count() > 0)
+	
+		var moving_piece_track_index: int = moving_piece_animation.find_track(current_animation_path)
+	
+		assert(moving_piece_track_index != -1)
+	
+		var new_animation_path: String = str($AnimationPlayer.get_parent().get_path_to(current_sliding_piece), ":position")
+		moving_piece_animation.track_set_path(moving_piece_track_index, new_animation_path)
+		current_animation_path = new_animation_path
+		
+		moving_piece_animation.track_set_key_value(moving_piece_track_index, 0, current_sliding_piece.position)
+		moving_piece_animation.track_set_key_value(moving_piece_track_index, 1, missing_piece.position)
+		$AnimationPlayer.play("MovingPiece")
+	else:
+		commit_slide(false)
+		update()
+		check_solved()
 
-func commit_slide():
+func commit_slide(audio: bool):
 	assert(current_sliding_piece != null)
 	assert(current_origin != Vector2.ZERO)
 	
@@ -244,7 +248,8 @@ func commit_slide():
 	swap_pieces(missing_piece, current_sliding_piece)
 	reset_position(missing_piece)
 
-	$AudioStreamPlayer.play()
+	if audio:
+		$AudioStreamPlayer.play()
 
 	ensure_validity()
 	reset_slide()
@@ -264,11 +269,11 @@ func swap_pieces(a: Piece, b: Piece) -> void:
 	b.taquin_index = a_index
 	pieces[a_index.x][a_index.y] = b
 
-func shuffle(count: int) -> void:
+func shuffle(count: int, speed: float) -> void:
 	while count > 0:
 		count -= 1
 		var direction = rng.randi_range(Direction.UP, Direction.RIGHT)
-		move_piece(direction)
+		move_piece(direction, speed)
 
 func check_solved() -> bool:
 	for c in range(columns):
@@ -380,8 +385,6 @@ func init(pieces_order: Array, hidden_piece: int) -> void:
 
 		pieces.append(pieces_row)
 
-	shuffle(difficulty)
-
 #
 # Signals
 #
@@ -391,7 +394,7 @@ func _on_Timer_timeout():
 func _on_AnimationPlayer_animation_finished(anim_name):
 	match anim_name:
 		"MovingPiece":
-			commit_slide()
+			commit_slide(true)
 			update()
 			check_solved()
 
@@ -411,6 +414,7 @@ func _on_NewGamePanel_start_triggered(preferences):
 			columns = 5
 			difficulty = 30
 		_:
+			assert("Invalid value")
 			rows = 4
 			columns = 4
 			difficulty = 10
@@ -420,4 +424,4 @@ func _on_NewGamePanel_start_triggered(preferences):
 		pieces_order.append(order)
 	var hidden_piece = rows * columns # Last piece is hidden
 	init(pieces_order, hidden_piece)
-	shuffle(difficulty)
+	shuffle(difficulty, 0.0)