That was fun! The cute style is perfect! Great Game!
Some suggestions:
- make the foreward movement not instant, but accelerate/decelerate, that would make it more "fluid"
- add Sound-FX for engines, shooting, hitting (maybe no "boom" but a comic style "boing" ;-) )
- some visuals for the "hit"-events, like smoke, or stars (as the hits are not terminal)
Some further suggestions:
- local multiplayer for one tank: one player is the driver, the other one operates the cannon - in splitscreen