Too hard for levelling, and when you do level up, you get a pretty small award if you worked really hard to level.
It also sucks when you're shooting and then you accidentally clicked outside of the screen, it's hard to shoot people caused of the slight pause after the click to the (game) screen.
Overall, it's okay. 4/5
Have anyone else noticed the trollface you get when you pass the trigger that activates the laser, and you quickly descend; you'll see the trollface since you can't go anywhere. Comprende?