Ah, this takes me back! I know Hideo Kojima despised the NES version of MG1 since it wasn't really true to his original vision, but that's still the version I enjoyed as a kid, so I'm glad you've taken the time and effort to remake it. Now to get to some details:
-seems like jumping can be used to do things you're not supposed to do, specifically, inside Building 2 close to the front entrance, there's a barrier just to the right. I was able to jump on the barrels/whatever next to the barrier, then OVER the barrier to the corridor on the right, thus basically bypassing the bulldozer boss. I'd imagine this could happen elsewhere in the game, though I haven't run around trying to do so.
-looking forward to that save functionality; it usually takes me 3-4 hours to get through this game since brain no work well, so I tend to have to break up my play time to deal with IRL stuff; if I need to go somewhere I'll just put the computer on hibernate so I can return to my place in the game, but I probably shouldn't have to do that; tl;dr: save functionality would definitely help folks that can only play for shorter time periods per sitting.
-were the end credits not meant to be read? 'Cause they're pretty durn small! (or am I misremembering that...)
-like others have suggested, increasing kick speed/adding a stun effect to it would make it a more viable move, though with all the ammo you can collect, there's little risk to just going full COD-style murderhobo and clearing all the rooms you move through, so it kinda feels like kicking isn't so necessary; now, if you were thinking of tightly restricting ammo availability, then kicking would become pretty essential for saving that limited ammo; ...hmm, maybe that could be part of a higher difficulty level or something, though that would venture further away from the original game.
-while I know that this is a non-commercial/personal-use-only project, I still worry a bit about the music and sound effects - which sound exactly like in the original game - and I wonder if those might prompt a C&D complaint or similar; are those also part of the Epic Games store assets you mentioned (which would mitigate that concern, I think)?
Thanks for making this re-make, and I'm looking forward to future versions!
Edit: forgot to mention that it runs quite well on my computer; here's my specs:
Alienware M17R4
Intel Core i7-10870H @ 2.20 GHz
32 GB system RAM
2TB NVMe Samsung SSD
NVidia GeForce RTX 3080 Laptop GPU, 16GB GPU memory
Windows 10 Home