Mega Man World 3 DX is a Game Boy title and is likely a fan-made enhanced version or a ROM hack of an existing Mega Man game, adding to the original's content or improving the visuals and gameplay. (Information on exact developers and publishers is often unavailable for ROM hacks).  Details of its additions or improvements would depend on the specifics of the DX version.

Mega Man World 3 DX

Medarot - Parts Collection 2 (Japan)