Fun game!
Took me some time to understand how to actually survive and get to the higher waves! It's not an easy game, although it may look like it at first. But I liked the challenge!
Nice mechanic that makes you think and plan ahead as much as possible, and be prepared to aim well or there's a heavy punishment.
I might have made a slightly easier timing between stopping and letting the player shoot for an easier learning curve, but that's just me. Good job :)