Its leaked. Its low quality. You can barely hear what the presenter says, but that doesn't make it less epic!
First footage of actually GW2 gameplay where a dev is running around in godmode (most likely testing out stuff before tomorrows reveal):
http://multiplayer.it/video/guild-wars-2-per-pc/guild-wars-2-gameplay-gamescom-2010.hi/
Edit: He states in the video that dev hax is turned on and he's invisible to the mobs. Thats why they're not reacting. Its most likely also why he does so much dmg and has so much hp.
First footage of actually GW2 gameplay where a dev is running around in godmode (most likely testing out stuff before tomorrows reveal):
http://multiplayer.it/video/guild-wars-2-per-pc/guild-wars-2-gameplay-gamescom-2010.hi/
Edit: He states in the video that dev hax is turned on and he's invisible to the mobs. Thats why they're not reacting. Its most likely also why he does so much dmg and has so much hp.