Rockman 4 Minus Infinity

Rockman 4 Minus Infinity is a Rockman 4 ROM hack by a Japanese person who goes by PureSabe.

It keeps the same basic plot as its source material, while adding a number of new features, such as all-new levels, bosses, and music, as well as a modern save file system. It also contains plenty of Shout Outs to other games, including enemies from other Mega Man titles, and many level design homages. Most of this stems from its usage of assembly hacking, allowing for deeper customization than other ROM hacking tools.