Super Mario + Luigi World Co-op (V4.1) is a ROM hack of a Super Nintendo game, likely based on Super Mario World or a similar title, suggesting a cooperative gameplay mode involving both Mario and Luigi. Version 4.1 indicates multiple iterations and refinements, suggesting a dedicated effort by the creator(s) to improve the game. Fan-made ROM hacks like these often feature modified levels, characters, and potentially new mechanics to enhance the original game experience.  The creator(s) of this ROM hack are likely within the independent ROM hacking community, with no formal association with Nintendo or any licensed entities.

Super Mario+Luigi World Co-op (V4.1)

Super Mario World Hack 6