The basic idea is one everyone's had for a while: Print a transparent OLED screen over some glasses and hook it up to a portable computer: Bam, instant HUD.
The rest of it is also pretty simple extensions on what an Android phone can already do.
That said, I wouldn't mind a version sans-viewfinder. Just have it do what current phones do and display a little thumbnail of what the camera sees when I'm using it. That way it's temporary, and not a permanent obstruction of one's view.
So it's all currently-existing tech, but I predict problems getting it all to work right. Contrast is going to be a real pain (you'll get ambient light bleeding through even perfectly "black" pixels) and you just know people are going to walk into stuff because they can't see.
Still, I'm glad some work is finally being done on this, and I'm certain that in a few generations eye-tracking technology will be added to it, allowing you to do some very impressive things with how its controlled and how it presents data.
I think it has the potential to be pretty cool- especially the map feature. It seems almost like a smartphone, fused with a pair of glasses. If I could, I'd try it out- maybe even buy it, if possible.
My only hope is that they make it simple to use.
Well, I guess a couple of my fears would be that 1) The display would be blurry, being that close to your eye and 2) trying to use it and end up bumping into people, dropping stuff, looking like an idiot, ect. Someone mentioned 'cheating on exams' in the comments of that video, too; that could be another problem.
While the idea for this tech is cool, a lot of things about it have me worried. Besides the obvious things others mentioned about one's view being constantly obstructed, and the requirement for voice commands that probably won't end up working all that well (and make you look like an idiot trying to make some of it work)... I mean, this is Google. Smartphones already track every ounce of activity you could possibly input-- do we really need Google glasses on everyone so Google can literally see every waking moment of someone's life?
I mean jeez, call me paranoid, but with the Internet in the state that it's in in terms of legal limbo, and with companies increasingly logging user data.... I think I'd be too terrified to use these things.
The one thing that did really impress me though (despite the requirement to turn on location tracking) is the GPS displaying your directions right in front of you, which is perhaps the most obvious, yet most beneficial use of an HUD like that.