This is a really nice game. I am a person who have fun playing shoot games, so this is a perfect game for me. But there is a problem you have to fix. Yesterday, I played 21 levels, but when I opened this game today, I had to play from level 11. This is going on for several times, and I'm starting to get mad. If you fix this, I will come back and give a 5 star rating because this is the only problem. Thank you.