This is a 90's game in spirit allright. One of the very few games where it's very possible to "solve" it with a theoretical max score, given how little you can optimize it once you have a set route. Or well, the max score implies sticking to one weapon but that's impractical to do, considering how the hyper shot can nerf it to the ground temporarily.

Good pixel art. Scary battles sometimes. It took a bunch of time to learn.