I think mega man x1-2 has some of the coolest secrets ever. In X1 I love using the haduken on enemies especially since its one-hit kill. Also the first time I beat the game I had to use the haduken. Sigma and his dog would utterly demollish me before I could get to his last form lol.

In X2 you would be able to do the Shoryuken. I never really use that much though but thought it was really cool too.

Is there anymore street fighter moves you can learn in the X series? like could you do Tatsumaki Senpuu Kyaku (that spinning leg move) that would be hilarious

I can still remember how excited I was when I discovered the Haduken in the original X.  To this day its still one of my favorite games of all time.

I remember when Mega Man X was still new in town and my sister's bf told me you could get the hadoken. I was like no way no way no way, obviously this was before the internet was popular so there was no way to confirm without actually doing it. Street fighter is probably my second favorite video game series after Mega Man and when we finally got the Hadoken and saw Dr. Light with Ryu's headband on I almost crapped my pants. Ah, good times.