Very surprisingly, this one turned out to be my favorite so far. It does have a couple bad weapons or fights, but it's made up for in spades by a lot of fun fights, a lot of really cool levels, some really fun weapons, and i like how it handles the protoman stuff before it goes into the final fight with Wily. This one felt like it had a bunch of energy behind it's creation, and also the mega buster feels a lot better than in 4 now that it's got a bigger blast radius. It's pretty neat. As per usual, here's the boss order.

8- Wave Man
7- Crystal Man
6- Charge Man
5- Stone Man
4- Napalm Man
3- Star Man
2- Gyro Man
1- Gravity Man