The gameplay footage is awkwardly played twice and -- trust us -- does the actual game no justice in terms of graphical fidelity. However, it does give a glimpse of the scene in which Agent 47 has to escape a library full of cops. The scene where he smashes the cop over the head with the statue is the more "stealth" approach, while in another scene you can see 47 taking a hostage to walk out of the place.
Update: The gameplay footage appears to originate from a Danish news program that aired during E3. Thanks, Patrick.