28 Days Later is not a zombie movie. Let's take some points; Not undead. Infected people (Note: still alive), but still living. Just very, very angry people who'd like to rip you apart.
Storyline wise, yes the ending was good (dispite my absoluate hate of it's poor continuity). But gaming wise, WHAT THE FRIKING HELL. As for Halo 2's. It sucked.