Not a huge fan of the angle you used (I feel like your head should've been 1/3rd away from the left of the screen, so we get a more central view instead of the far right like in that video) but that could've just been me. Looks really awesome, though. I might have to look into building one and then checking out my school's GoPro camera to film some stuff.
Here's another video I shot with it earlier:
http://www.youtube.com/watch?v=aeeKzmFqP5A This was before I put straps on to secure it, and instead I was using a long piece of rope, it moved around a lot more, but for some reason the angle wasn't as tight. There's play in the pipes, so maybe they got bumped and I didn't realize it had moved the shot tighter. I agree though, I kind of liked having the view with me taking a little more of the screen. It looked a lot more like you were watching Mass Effect or something

I like the backpack angle. I was wondering how that rig made things look and I'm quite impressed with it.
What camera were you using and what settings? The only video I've really made with my Hero2 had some quality issues I didn't like with 720p at 60fps.
Basic GoPro Hero on 720 @ 60fps

The youtube video lost a lot of quality, something about the rendering process killed it, and I could probably rerender it to make it far more crisp again, perhaps with better editing software. I assure you I love the quality I got with those settings in the raw footage.
Also I used absolutely no image stabilizing in the video, all the clips are raw other than my splicing them all together.
The rig I made was from this video, they have a link to the pvc sizes to use:
http://www.youtube.com/watch?v=hOdu1Zl1lic The only difference is that I don't have a belt for it, I still tied the bottom down, but I did have some difficulty throughout the day without a firm hold on the bottom
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EDIT: Y'know, I think I figured out what was different about the angles between the video in the OP and the video I just shared that I had taken earlier. In the OP vid I'm wearing my molle gear and the hydration bladder on my back is full. In the video I posted of the nerf war, I'm just wearing a hoody, no gear. I bet the bulge on my back tightened the shot.