Fortunately at least the 10 minutes or so are spoiled by a Russian voiceover so most will likely be put off from watching it. It releases near the end of August.
Apparently someone very naughty leaked a press preview build of the game from Eidos Montreal, but it was however a limited version and didn't contain the full game. At least that's what's being reported over on.
See below for the first 10 minutes of the new Deus Ex, but beware the Russian guy voiceover. Deus Ex: Human Revolution releases on Xbox 360, PS3 and PC August 26th.