It's okay. Sometimes the upgrades were a bit too far apart and the coins really filled the screen up, making survival mode almost unplayable after about 6000 meters. The upgrades are great though, and each definitely changes the game. I played for about 2 hours. So despite the flaws, it's still very addicting. Small thing, sometimes I would open a chest, towards the end of the game, when I was almost totally leveled up, and it would revive me even if I didn't want to be revived. I would suggest a "kill yourself" button to help with level grinding.