Only display "clear" message for a short time

game.c

@@ -109,9 +109,9 @@ static shape_t shapes[MAX_SHAPES];
 
 static unsigned entity_count;
 static unsigned shape_count;
-static unsigned asteroid_count;
 
 static bool dead;
+static unsigned asteroid_count;
 static float aspect;
 static uint8_t counter;
 
@@ -461,6 +461,9 @@ void game_update()
 		return;
 	}
 
+	if (asteroid_count == 0 && counter <= COUNTER_MASK)
+		++counter;
+
 	ship_update();
 
 	for (unsigned i = 0; i < entity_count; ++i) {
@@ -501,8 +504,9 @@ void game_draw()
 		    shapes[i].connect);
 	}
 
-	if (asteroid_count == 0)
-		text_draw("CLEAR");
 	if (dead && !(counter & COUNTER_MASK))
 		text_draw("GAME OVER");
+
+	if (asteroid_count == 0 && counter < COUNTER_MASK)
+		text_draw("CLEAR");
 }