This is decently fun! Not the most crusty game, but I do like that you can change fire modes at any time. I don't think I tend to see that in asteroids-inspired games, that's actually a pretty neat idea... and the game also lets you move backwards, another thing I don't tend to see in this kind of game, which actually helps make it more fun.
I do think the boss might be slightly too hard, but eh, still, I like this one overall! It's simple but it's pretty fun. Just feels slightly less crusty than it maybe could've stood to be.