the movement space is too small, the game is too easy, no variety in enemies, and the ripple effect is annoying. it has massive potential, but falls short of the mark. it could be loads of fun if you added upgrades and maybe some objectives. :) and the graphics are quite nice.

didn't realize I could move for 4 levels.. didn't need to.

Not enough room to move around. The arena needs to be at least 2x as big to allow the tank to kite away from enemies. Or conversely you can make all the enemies and the tank 1/2 as large so there's less claustrophobic clutter.

Also, this type of game always benefits from gradually introducing enemies, so that they are memorable and unique. If you throw them all at the player in the span of 1 minute then there's no time to distinguish one from another or what enemy types have what special abilities.

Interesting choice of graphics

good potential, but there is too much going on in not enough space, as well as teh distraction of those ripples in the background.
get rid of the ripples and make the whole field bigger in comparison to the "tanks" and you have an excellent time waster game here.
I would keep the pen and paper style that you have, it is original and well done.

The pencil graphics what let it good.