I love how arcade this game feels, it's simple, it's short, it's engaging and it's really fun. The difficulty increases really nicely, not only because more enemies spawn and more frequently but also because your own shots can destroy the floor just like the enemies, making it unavoidable that the level itself becomes harder to traverse. Also thanks to the room rotation every so often it makes it so that you can't camp around, it forces you to move.
Astonishing job on this one.