SNES Classics: Mega Man X - Secret Hadouken!

After you have collected all special items (Heart Tanks, Weapons, Armor Upgrades, Sub Tanks,) head back to Armored Armadillo's stage. At the very last mine cart, jump so that you land on the wall above the boss door to find the secret Hadouken pod. Note that it isn't always there, and may take multiple attempts for it to show up. Just jump in the pit and start from the last checkpoint. This video actually took 4 lives before it appeared. To fire the Hadouken, you must be at full energy, then input the same command from Street Fighter II (Down, down-forward, forward + Y.) The Hadouken is ridiculously powerful, able to destroy any enemy or boss (except Sigma's final form) in only one hit.