Mega Man 9: Part 12: Wily Stage 4 (Robot Master Rematches)
As per Mega Man tradition, before reaching Dr. Wily, you have to face all of his Robot Masters again. You'll have to make your way to the room to face them all first, though. You'll be dealing with lasers on your way that you have to block and cover with the Concrete Shot.
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Here's the order I face the Robot Masters in as well as each of their weaknesses:
1st: Galaxy Man; Weak to Concrete Shot
2nd: Concrete Man; Weak to Laser Trident
3rd: Splash Woman; Weak to Hornet Chaser
4th: Jewel Man; Weak to Black Hole Bomb
5th: Hornet Man; Weak to Magma Bazooka
6th: Magma Man; Weak to Tornado Blow
7th: Tornado Man; Weak to Plug Ball
8th: Plug Man; Weak to Jewel Satellite
Beating each of these Robot Masters will spawn large health pickup that you have to... pick up... before you can leave each of their rooms and move on to a different one.
Wily Time after this! Watch it here!:
https://www.youtube.com/watch?v=CicL_vmaoKI