I couldn't watch all of it, it had a weird bug where the audio would start and continue to play even if paused, and there was a slight delay from the actual video's audio. o.O
Anyhow, my $0.02 is that it's going to look bad to at least 1/3 of the people using it, it's going to have a noticeable delay and it's going to be more expensive in the end than just buying a good video card. And I'd like to reiterate that I haven't seen the video in full since the dual audio/delay kind of makes it hard to know what's going on...
Also, it seems like it'd be hard to judge the delay in the demonstration since the computer is facing him, so can you really see what he's doing and when it registers? The delay between the pc and the projector would also have to be taken into account, but it can't be that noticeable, if there is one at all.
The best thing about this, however, is that if you're traveling with like a laptop or something, you could easily play all sorts of games.
Oh, and iphone/ipod touch. That shit is just whack. If you can actually pull that off, and enjoy playing it at whatever the delay is, it would make it worth it. Provided that the controls are good, though.