The idea for the game is really cool, and I do like the artstyle a lot. The tutorial broke for me, but it seems like using Firefox fixes the issue.
As for the main levels, something that bothered me was that collisions didn’t impact the gun’s velocity. It would just slide off walls and keep moving at the same speed after. I also think adding some more restrictions to the player (like limited fire rate or a cooldown on the slow) would make the design feel tighter. As it is, I could spend all my time in slow-mo and spam bullets until they hit, which trivializes a lot of the challenges.
There’s definitely potential in this idea, with a few tweaks and bug fixes this could absolutely be one of my favorites.