Super super fun game. Great work on the audio, shake, and freeze frames in this game. Very JUICY game.
One thing that would make it more satisfying is if you tied the left/right punch to the mouse buttons and let you alternate punches with a slightlyyy lower cooldown than the current cooldown (and keep the current cooldown for pressing the same direction). I felt like the punching was too sluggish, and I felt a slight disconnect that the punch direction was random relative to what I pressed. I felt like I wanted to chain my punches when a bunch of the gummy bears were swarming me, but was punching them so slowly. This consistent mouse key to punch hand would also help make it known that you can right punch while you have a gun, though I might have just missed a cue explaining that.
Also, I feel like after you introduce the guns, you need to litter a few of them around, I had to dance around the guys shooting too long to grab one, which doesn't feel great when you just got access to the gun. But the running through enemies in a path was fun.
I also had the bug in the last level where you spawn underneath, but I thought it was kinda cool. I got to stalk under the enemies and jump up at them to start the level where I wanted to. You could incorporate that into a cool type of level entrance.
I feel like you could transition this into a full game, but designing all the levels might take a while. I know everyone's doing it, but an endless horde mode in this game world could be really fun, and creating that could help you release a game that feels"full" faster. I feel like you could use one more movement option, like a grapple, or a slide, or something new.