Major Shatterhand vibes and some Batman vibes too -- definitely hit the early 90's feel.
God-tier graphics -- great use of color, and tiles and sprites are very detailed. I love the cutscenes graphics as well. There certainly was a lot of attention to detail in this game.
Sound is great and I like that you also took the time to add options (I always forget about this for game jams lol; that said it would be nice for a 4:3 aspect ratio).
The game also teaches you how to play in clever ways and the levels seem like they are just the right size. One minor suggestion I have is to maybe change the color of the machine targets for the first boss -- they blended in with the environment and I initially thought I was supposed to shoot the gun.
In any case this is an excellent game, I'd certainly buy it at a high price if you port it to the NES and slap it on a cart using a mapper from the time (90s).