Super Street Fighter 4 Zero Damage combo video, part 2
@SAMURAI It is from Super, indicated by the ultra bar. You can still canel Ryu's hadouken into super but you can't activate the super after the hadouken recovery while the hadouken fireball is still on-screen.
DMG Inthul Fei Long Super Street Fighter 4 matches
Due to the input leniency of the SF4 series players can get away with a degree of sloppiness that would not fly in other 2D fighters. Hence, the precision afforded by a joystick over a pad is not nearly as significant.