Very cool idea! I like how colorful it is. Figured out the best strategy would be to move into one of the corners, deflecting all bullets from there. Turned out that's not the best strategy, as it will glitch you out of the map. :D Which is especially problematic, as you can only press "R" to restart when you're dead... Also the total absence of sound makes it feel a bit lifeless, I used "sfxr" to generate a few basic ones for my game. Give it a look. There's also www.bfxr.net, if you don't mind a flash version. Really liked the two different enemy types btw and how the gunners announced their shoot in advance. Good job! :)
My game: https://njamster.itch.io/wonkey (playable in browser, not mobile friendly)