Pretty cool! Slowdown mechanic works well (I think it'd be better if it didn't affect the player bullets though)
Some other suggestions:
- Either alter camera angle or increase bullet size - a few times it felt like bullets were going through enemies, I think because of the camera angle
- Maybe a short flashing animation in spawn spots half a second before the enemies spawn - a few times I nearly ran into them as they spawned in my path
Good job!