Super Mario 64's Mario is the hero of Ocarina of Time: his jumps, moves and physics in the full game, from your own ROMs.
Super Mario 64's Mario is the hero of Ocarina of Time. Not a skin: the real thing, running inside OoT's world.
Mario is driven by libsm64, the Super Mario 64 decompilation built as a library, so he moves exactly as he does on the N64: running and the speed ramp, long jumps, triple jumps, backflips, side flips, ground pounds, the whole animation set, his own sounds.
The world is Ocarina of Time, running in Ship of Harkinian (the PC port built from the zeldaret/oot decompilation). Mario walks OoT's Hyrule, collides with its walls and floors, and enters its houses and loading zones - walk into a doorway and the scene changes just as it does for Link.
You need your own copies:
No game files are included or downloaded.
Controls: the N64 pad as OoT uses it, with Mario's moves on it - A jumps, B punches, Z crouches and ground-pounds, the stick runs, and OoT's camera follows him.
Credits: Ship of Harkinian (HarbourMasters) for the Ocarina of Time PC port, libsm64 for Mario, zeldaret/oot and n64decomp/sm64 for the decompilations, and Nintendo for the two games this celebrates.