Fellow solo dev here that also weirdly enough made a challenging cat-based 2D side scroller!
I liked this and appreciate all the custom art resources.
I thought it was way too hard, and again, I'm a fan of challenging 2D platformers. But this was like OG Contra hard, which is way too masocore for my tastes.
The shotgun (the only gun I found? there was a change weapon button but I never found another gun) needs work, it needs to sound less puny, it needs to do more damage, and it desperately needs to have some spread.
Enemies are too tanky and saturate the level with a truly ridiculous number of bullets, bordering on bullet hell. Bullet hell is fine but the game has to give you SOMETHING to deal with it, but in this you have no double jump, no dash, no slowmo, no "panic button" kill the whole screen bomb, just a single very underwhelming gun.
I got softlocked on the end boss because I couldn't hit him from the bottom of the arena or jump back up out of the bottom.
Also, I really disliked the music, but that's a matter of personal taste.
Once again, I love the premise, the title splash art is AMAZING, the amount of custom art is impressive, and I really dug the UI choices and the "add quarter to continue" gimmick was very cool!