A pretty fun and short game. The platformer aspect is pretty decent, but I'll say the gunplay is even better.
The game would probably benefits from having a wider aspect ratio just because you can barely see where you are going most of the time and enemy just runs at you way too fast because you get too close. I have a feeling that level design suffers too just because of this. The bullet emitting light is a pretty clever mechanic but as I said, because the aspect ratio was so small it hinders the usefulness of it.
Screenshakes were overdone a bit too, it feels like Hiroshima when you're firing that machine gun. Probably needs an epilepsy warning just because with the flashing and screenshake. But the rest of the gunplay is very satisfying.
Boss fight was surprisingly easy, I just stood under a platformer and shoot at one direction for a couple minutes without even moving.
Oh, and one last thing, the death sound was 300 db higher than all the other sounds in the game.