Mega Man 3 - 2 - Doc Robots, HO!!!
And this is where I draw a line with Mega Man 3: the doc robots. You have to revisit 4 previous stages (Spark Man, Needle Man, Shadow Man and Gemini Man) each occupied by 2 doc robots; each programmed to fight just like the bosses of Mega Man 2. Only way more annoying. They're a lot bigger, it's a bit harder to avoid taking serious damage from them (screw you, Quick Man doc robot) and in my personal experience, they feel like a complete waste of time to implement them here. Capcom took previous bosses and turned them into a meaningless gimmick. While Mega Man 10 also did the same thing, I felt like they did it better.
This is why I can't put Mega Man 3 in my top 5 Mega Man games ever. While the game has done significant changes to the franchise and is a pretty fun game, the doc robots really hurt it for me. They really do.
So who's up for some cheap nostalgia?