The levels aren't changed, but the enemies are! It's a fun hack made before figuring out the level structures for the game, but all that's different here are the enemies. It's by no means bad, but just know that the enemies are all that's different here.
Frank's Super Mario Land Hack
2003, Frank M.
golden_road15@hotmail.com
This hack changes the enemies in the levels, making them harder, especially once the game goes into hard mode.
Super Mario Land (World) (Rev A).gb
CRC32: 2C27EC70
MD5: B259FEB41811C7E4E1DC200167985C84
SHA-1: 418203621B887CAA090215D97E3F509B79AFFD3E
SHA-256: 49FBD2F61F953D5EF28CAB73E357E524C3009AD19FCF30F6A9EE0AE273BE41DC