I think when you roll into a ball you should be indestructible and when you come out of the ball you should spring out not stand still and open, i loved just rollin around makes the massive maps more bearable, try changing the gameplay to more of a mothership style, potentially great, 4-5/5
Straight away I noticed the sentence 'more points for killing the rebound' only thing I've managed to kill is the soldier, rate this if you are struggling to kill the rebound lol.
Possibly a great game but you need the first few levels to be easy just to build your cash and set up a defence, rate this if you think the publisher should take this advice,
Best tactic I've found is choosing the third character and keep upgrading power, use the secondary weapon (spining fireballs), activate auto fire, you can then shoot as fast as you click, you just get a massive wave of shots killing everything instantly, rate this for others to see.
Great game, found a glitch that makes the game alot easier though, if you activate auto-fire on the first character you can shoot as fast as you click the mouse button, not sure about the other characters, great game 5/5