I always appreciate it when folks make games in fantasy consoles like this, it's a great way to show your skills and bring some familiar-yet-unfamiliar retro vibes!
I think the Metroidvania aspect exists but is still lacking; while the backtracking and skill-gating were there and done well, the game flow was otherwise fully linear; you need to obtain everything to make it to the next area and there isn't any room for non-linear routing (taking alternate paths, optional upgrades, etc.). But there's definitely a lot of potential to develop what you already have into something big for SMVM.
Keep up the good work!