Mega Man 11 - Block Man (Buster + Speed Gear Only / No Deaths)

Future levels are purely Buster-only without even the Speed Gear! Block Man is probably the boss I have had the most trouble with; his first and third phases are ridiculously easy, but his giant golem phase took a while to get down and it deals a ton of damage. His stage is still neat and the minibosses are a lot easier once you realize they always use the same pattern.