Ummm from what I've read this really is not that useful. There's really to much interference from the subconscious mind to control a video game effectivelly by micro-muscle movements.
I would compare it to dragon naturally speaking- theoretically awesome idea. I mean you do speak faster than you write, but in practice it is still better to use the keyboard, because the recognition software needs training, and it really isn't that accurate. (At least my version wasn't, it never transcribed what it should).
But if you don't have arms or legs (to use a keyboard for the feet) I guess this is the best way for you to play left 4 dead 2 or GTA 4.