I would've rated this Easy if it had midway points - it can be frustrating to replay an entire level because some of them are kind of long. The design's not bad and it likes to throw bonuses at you mid-level. The final boss has a bug where if you carry in a shell, for example, the boss won't spawn, forcing you to die. Music is also broken when the Nayru statue spits a fireball.
The old music ports are horrendous to listen to and the graphical clashing is some of the worst I've seen: you've got Game Gear styles mixed with old and new NES and SNES games because the game tries to make be an homage to every popular retro series the author could think of. Furthermore, you can't tell when Alex is big or small. There are only two tell-tale things to look out for without bumping into things: Pressing up while small will change his eyes if he's small, or if you're wearing red then you have the fire power... but it pisses me off that the hitbox is completely out of line with the graphics while "big". Should've used the health meter: it was around back then.
A lot of the redraws of the enemies are cool since the behavior isn't far off from how they act in the original games, but sometimes it can be hard to know what behavior certain sprites will have.