I'm not really into platformers like this. My experience with the genre basically boils down to Celeste and Hollow Knight (which is hardly a platformer most of the time), but I really like what you have here! The movement is very smooth, the spinning and slingshot are great mechanics, and the way you implemented checkpoints is perfect and completely prevents any frustration, which kept me happily playing all the way to the end.
I'mma be honest, though, and say I had a little trouble with the slingshot sometimes, because I kept slamming my cursor against the edge of the game window and accidentally releasing it before I intended to (but that's probably just a skill issue on my side). The only real problems I encountered were when the IRS appeared to talk to you between levels. On my first run, the cat got stuck before a one-way platform, and I had to restart the game to continue playing. On another occasion, the cat's dialogue box was half cut off by the edge of the screen because the dialogue triggered while it was too close to the edge. But that's it! Other than these minor polish issues, you've made a truly enjoyable game that I can eeeeasily see becoming a full game with more levels and all!