Looks like a cool idea
Okay, so maybe not a totally new idea; but the idea of reading the muscle movements in the forearm to detect finger movements in a pretty cool idea - and it removes the glove from the equation, for a more functional if less bad-ass look :-)
The ergonomicist in me is skeptical. The best way to detect finger movements is the fingers. Detecting it way back in the tendons of the forearm is a lot like trying to tell what you're writing with a pencil by holding onto the eraser. Yeah, you can do it... but if you're trying to use the eraser as the input device but holding onto the sharpened bit, you end up using your muscles pretty much exactly wrong. This way lies frustration and carpal-tunnel. The other thing people who are big on FYOOOOOOOOOCHUR but low on usability always focus on are big, grand gestures that look awesome in kickstarter videos but suck ass in real life. Repetitive strain injury is a bitch and one of the best ways to get it is by doing big, needless, no-feedback motions that accomplish small things. Like the dude using his armband to play COD4 or whatever he was doing - you can buy pistol controllers. Hell, Duck Hunt is 30 years old. But most people prefer to play with their thumbs not because they hate realism but because if you're going to engage in a firefight for fun, you go all the way - that's what paintball is for. And if you're not going to engage in a firefight all the way, half-measures just give you weird cramps and strains after a while. Far better to kick back on the couch. I recently got rid of a glottal-pulse-to-MIDI converter (the electronics fried, thus saving me the grief of figuring out what to do with a $1500 gadget with a double-digit serial number). It actually tracked the electrical impulses of your epiglottis and turned it into pitch and volume information for synthesizers. Thing of it is? pitch to midi is waaaaaay easier to do these days. I mean, back when this thing was built voice recognition was science fiction. Nowadays you can buy a free program for your iPhone that'll do the same thing. The tech this thing is using was pretty much abandoned back in the '80s - not because the circuits weren't fast enough or anything, but because the ergo sucks, the feedback is non-existent and the novelty wears off really quickly. I've been wrong before. I'll be wrong again. But "user input" is a mature market segment with a bunch of clever people earning their living trying to show each other up. Ole Billy Ockham would argue that a $150 preorder gadget probably doesn't incorporate much that hasn't been rejected by that crew.
There's not often anything truly new under the sun. I'm okay with improvements and extrapolations of old ideas.