The game is really great, 5/5) But, I have some suggestions:
1.The Firethrower and Bazooka are too overpowered(as for me) coz they can kill TONS(!!!) of monsters easily;
2.The last monster, that one on a ball, is too(TOO!!!) easy, and there are 2 ways, add new stronger mobs or nerf the weps;
3.After competing the game, weps and skills should reset, coz it ruins the game completely;
4.You should make hotkeys for skills and shop, coz during the battle it is hard to acces them;
5.The box.... As for me the game was too easy, coz the box is easily killable with a flamethrower;
I hope that I'm not alone, and others will make so the developer could see this, plz + this!)
This game is 2 year older than the game you mentioned in your comment. Details in PM.