Stage select screen:
- Air Man: Mega Man gains the Rush Jet, necessary to get some items in Crash Man's and Metal Man's stages;
- Crash Man: he's weak against Air Man's weapon;
- Metal Man: he's weak against Crash Man's weapon; also, Mega Man gains the Rush Marine, useful in Wood Man's stage;
- Wood Man: he's weak against Metal Man's weapon; also, the Rush Marine allows a shortcut in the stage.
- Magnet Man (down-left hatch): he is weak against Metal Man's weapon; also, he suffers the least damage from the weapons of the other three Robot Masters in the Teleport System;
- Hard Man (upper-left hatch): he's weak against Magnet Man's weapon; also, his weapon is effective against both Top Man and Quint, but you need a stage between them to recharge it;
- Top Man (upper-right hatch): he's weak against Hard Man's weapon;
- Needle Man (down-right hatch): he's weak against Top Man's weapon and, to a lesser degree, to Air Man's weapon.
- Quint: he's weak against Hard Knuckle; he has 32 HP instead of 19;
- Dr. Wily: all the three Wily Machines are only vulnerable against the Arm Cannon and Quint's weapon; the latter is best suited against the second Wily Machine; note that the first two Wily Machines only have 12 HP each instead of 19.
Note that in the list above Wood Man's Leaf Shield and Needle Man's N. Cannon are not used against other bosses, therefore feel free to use them during the stages.
Also note that the Leaf Shield consumes energy only when it is thrown, not when it is created; therefore, you can select it, make a shield, let the enemies hit it, then go to the menu screen and de-select it without any energy consumption.