For a direct comparison of gamplay altering abilities like in MM, there is this one PC indie game, Aquaria. (I'm sure a budget PC from 10 years ago can run it.) You learn songs that let the fish-girl heroine switch between several forms or directly influence the environment. Many of those forms have no offensive abilities but are required to explore the sea and advance, so you be switching between them as often as in Majora's Mask. It's more of an underwater adventure game than an RPG, but it comes with the exploration of adventure games. The puzzles are also a little simpler, with it being a 2D sidescroller game, but still require thought.
And the Shantae games have item/magic altering gameplay like tranformations that affect combat and puzzle solving. That's the only other games I can think of to use transformations/items to vastly alter gameplay like that.
finap said:
Masks aren't at all a necessity. I'm just looking for a game that has gameplay based on items, to affect battle style and adventuring, whether it's a sword, bow, sandwich, i don't care.
Well, almost any Metroidvania(a sub-genre of action-adventure) game has those concepts (exploration based on items, combat can change depending on what abilities you have, large world for adventuring). The two games I listed above are Metroidvanias. The Zeldas come close, being item based (and Zelda has always leaned far more towards that genre (or platformer for the 3D games and the 2D ones that have a jumping item) than direct RPG). Tomba(PS1 game, now on PSN) is one with more RPG elements. (Think Zelda if dungeons and the overworld bled together.) Castlevania and Metroid are the namesakes so most of those count.
One last one to really check out is Okami (and its DS sequel if you liked it). It
is Legend of Zelda, except with the Shinto sun goddess in warrior wolf form instead of a 10-16 year old boy, and it lives up to that description well. You gain brush powers to heal and undercover more of the land. Many of those powers also aide your main weapons in combat. (Two words: Power Slash.) Too many, people have dismissed this game, either for the gibberish spoken dialog or the Japanese watercolor art style, and they're passing up a truly unique gem.