Here is a complete hack of Mega Man 5 which changes all the level layouts and background graphics into Mega Man 3.
Update v1.3: Adds the original Mega Man 3 music.
Megaman 5 (U) [!].nes - GOODNES 3.14
CRC32: 5E023291
MD5: D7D22BF9EDFB16469975F7F4D8DA518F
SHA-1: 1748E9B6ECFF0C01DD14ECC7A48575E74F88B778
SHA-256: 32BD2B4ECD2129AA5337AFE9171696EF35646D3FD597339AEBBA19221764521C