Nice simple game without any (at least i haven't found any) bugs, it was a bit too slow for me, maybe you could add different difficulity or make simple ai for the enemies.
Also one thing i found that i ended up not shooting down corrupt shripms (the one that shoot out projectiles) because it was way easier to dodge them instead of dodging the bullets, you could make a punishment for missed enemies or make them linger on the screen. But overall pretty fun game!