This is SUPER polished!! I really appreciate the amount of effort that went into making it FEEL good to play, such as the pitch-scaled sounds when destroying the various shape types, the camera shake when firing, the particle effects when the shapes blow up, etc.
While I did find the gameplay fun and engaging, I personally think there were two flaws that tarnished the experience for me:
1. Having an infinitely scaling score multiplier felt bad to me. It makes it so that what matters most is building it as high as possible in the early game so that you can have a 100x multiplier in the late game where the most enemies were. The moment I lost my multiplier in the late game, it felt as though the run was pretty much over already, since building it back up would take too long. I think having a multiplier cap of like 5x or something would have made it feel a lot better to me; you'd be rewarded for going on streaks, but not immensely punished for losing it. I also think needing to build to each new X multiplier would have been nice (e.g. 5 kills for 2x, 10 kills for 3x, and so on)
2. The recoil gimmick was more frustrating than it was entertaining. The vast majority of the three games I played I spent blasting myself into a corner, and pretty much staying in that corner for the rest of the game, because I believe there's logic that prevents shapes from spawning too close to you. It's good that nothing spawnkilled me in the corner, but not good because I don't think I was engaging with the game the way you wanted. I found myself wishing I could just move around with WASD, which part of me thinks would have been fine, since I don't think the recoil was important for the game's theme.
With all that said, this is still definitely in my top 3 entries for this jam!! My high score was 2,489,500, with a 182x bonus streak :)