Really nice and fun game.
I agree with the others, it would be a lot easier to play if every control had a different button instead of switching between them.
Bug: I'm pressing D, and I'm moving to the right. I then press W and D at the same time, I move diagonally. I then keep pressing W only, at this point, the ant is still facing right. So if I'm shooting, it continues to shoot to the right even though I'm now going only upward.
Other than that, the game is very fun.