This game is actually pretty great!

The passion and effort you put into this is apparent, and it makes it all the more fun! It is simple design, but the little things you put there, like the lore behind the game and who the enemies even are, shows that you really want to make something of your work. I enjoy the classic aspect of taking enemy weapons and getting upgrades, and using your fists when all else fails. 

Idk if this is mostly because of the original game or not, but think the sound design is one of this game's strongest suits. I know exactly which enemies are in a room just from their voices alone! I can't always see healing items and weapons, so the sounds they make are an excellent way of telegraphing that they're there. 

I would recommend some small touches, like making the objects breakable (are they breakable?) and maybe some kind of dash or roll for enemies with guns of their own. I think you have the creative mind to come up with a bunch of cool and unique touches to this game!

Feel free to give some feedback to my game: https://wasabiiii.itch.io/grass-elemental-demo-demo

I also use Gamemaker, it's my saving grace lol. I've heard of its light 3D abilities, so it's pretty cool to actually play a game that uses them :)