Goodnight, Monster World
My fave 8-bit game after SMB 3 and still one of the best MV/Platform Adventure games if we include later versions and fan remakes (talking about the 2008 Dragon's Curse remake for PC here).
The game has excellent presentation that surpasses even some 16-bit games, the forms are distinct and fun to use, the pacing is great, and there are cool secrets like being able to switch or create platforms anywhere. There's even some non-linearity in the dungeon order if one so prefers. Last but not least this is also where the whole "beginning of the game ties into the prequel" trope comes from afaik, which was later used in Symphony of the Night.