To be honest I wouldn't install such a game, let alone buy it. The game has no purpose, the AI is basic, no collision, almost no animations, the boom is odd as nothing explodes.
Enough about my personal opinion.
I managed to open up every level. The first 2 "unlocked" ones i opened them up even twice.
I do not know when my trial expires.
You have some problems, I'll highlight a few:
1. the menu cannot be accessed unless you die
2. the joystick activates car (?) movement while WASD has 8 directions, it should be the same
3. no error message when i try to buy a skin, no output whatsoever which makes me think i'm clicking an image
4. the maps are higher resolution than the sprites which makes them look like they're levitating quite high
Hope I didn't disappoint you with my critics.