Don't make your game pay to win.There are many other fun games we can play at play store and you are not the best.So don't make disappoint to us.If you game can't win even try 10 or 20 times, I think they will leave your game and pay attention to others which they can go forward.So, don't make impossible missions in game.I think nobody wants to play a stage more than 20 times.If you want to sell, do it gently.Dont make push.