Mega Man Anniversary Collection Cheats

In Mega Man 1, when using a weapon that goes through an enemy --- Rolling Cutter, Thunder Beam, Ice Slasher, or Fire Storm --- press Select (L+R on the Gamecube controller) the second the weapon hits an enemy. After you press Select again to unpause the game, the weapon will hit the enemy a second time. This makes a joke of virtually every robot master battle in the game, so long as you have a weapon that can be used in conjunction with the glitch.

Unfortunately, this was fixed in later versions of Mega Man, and does not work in any other title besides Mega Man 1.