This is a worthy entry into the zombie canon, though it's (lack of) length leaves it feeling a bit underdeveloped, almost like a really good Master of Horror episode more than a feature film.
Michael arrives at his ex-girlfriend's apartment in Berlin, delivering her keys and hoping to rekindle the romance. She's not home, and while he's hanging out waiting for her to return, he meets a teen guy who is working at the apartment. Then they look out the window into sort of a courtyard of the apartment block, and there's a full on zombie attack happening. The rest of the movie follows these two guys as they try to escape the building to the harbor, where news reports suggest there's a ship ready to take on survivors.
Much of the movie is told through various windows in this crappy apartment.
The budget seems to have dictated much of the action here, so there's a bit of a claustrophobic feel--the whole thing takes places in a single Soviet era apartment block, which are always so damn bleak. Dilapidated concrete exterior, crappy plaster walls, metal institutional doors, etc.
But this movie does have some game. The zombies are cool and fast in the 28 Days vein, but the director also shows some balls and tinkers with the zombie rules a bit. One really cool innovation is that these zombies are caused by some super-virus, but an infection isn't an immediate death/zombie sentence. In fact, the virus seems triggered by anxiety/aggression, so if you get infected but somehow stay calm, you might not develop the full on batshit zombie behavior. So one cool subplot is that people are trying to get their hands on sedatives to keep themselves (or loved ones) mellow even after infection. This kind of medical zombification gives the whole thing a more realistic (and thus scarier) feel.
There's a couple less interesting things that happen, such as a romantic interest for the teen boy that seems to come out of nowhere, but overall, this is a pretty fun little ride. Also, the two main guy leads are both very very good.