Probably a known Megaman X Fact.

[Berry]

In Megaman X,there is a reference to the Capcom series Street Fighter, a hidden upgrade capsule housing the Hadouken Fireball (complete with X actually yelling "Hadouken!" in a high pitch voice) upgrade was placed into the game. It is not known why X does not yell "Hadouken" in Mega Man X Collection.

You can access it in Armored Armadillo's stage after collecting all 4 armor upgrades, all 8 Heart Tanks, and all 4 Sub Tanks (note that you don't have to fill the Sub Tanks). Before you make your way to the end of the level, farm extra lives at the start of the stage by killing the fat bat repeatedly. Make sure your lives counter is 6 or more (more if you're prone to dying while trying to reach the end of the stage).





Note:I don't know if everyone knows this but it is worth the shot.