no, she doesn't cheat. That's the Mockball glitch, which has been known since 2001.
BTW: RADIX WHERE THE HELL CAN I CONTACT YOU?
just wanted to make a quick change to both my :36/:38 comments. I'll (or could you) PM you later at Mills' boards, that is if the m2k2 board isn't still alive.
...If the Mockball I do at 5:54 is cheating, then why not the ones I do/start before that one in the same part, like at 2:13, 2:25, 2:38, 3:43, 3:51, 4:39, and 5:04 not cheating?
I think that's the murder beam (plasma + spazer beams on at the same time). She charges up and shoots Mother Brain right in the face, then it repeatedly hurts her; makes the battle much faster. It also makes the game go all crazy and some sprites don't appear right and stuff. Although, really, I don't know a whole lot about Super Metroid, this is just what I heard.