At 19:40, the narrator mentions that nintendo swapped in a crab enemy to mario bros to replace the mouser enemy from doki doki. I don't remember any crab enemy when I played mario as a kid, and i do recognize that mouse bomb enemy. Am I wrong here?
The crab is a boss of world 5. But Mouser is still in the game at the end of world 1. I remember the crab boss being easier compared to Mouser, and thinking they should be swapped.
The mouser they swapped out had a harder room layout too