Well, there's good and bad here. The graphics are great; I like how all the enemy types are distinct, very easy to tell apart. The programming is pretty solid...except that on level 20 I somehow lost half my weapons and got stuck trying to survive with the short-range gun. That didn't last long, of course. The fact that the enemies randomly appear makes it "frantic" in a nice way. However, it's really annoying that it's another one of those games where you have to upgrade your "money" before anything else and you have to buy ammo after every battle. Another thing that was frustrating was that the coins will disappear after a few seconds; you can circle around a bunch of monsters to kill them, but is it worth it to spend one of your precious 3 health points to grab their coins? Also, please get someone who is a native English speaker to edit your text.
The hardest enemies were the eyeballs. Very annoying.