The cinematic trailer for The Sacrifice add-on offers a preview of some of the expansion's key battles and dramatic events.

Gameplay of the opening level in The Sacrifice, as seen on YouTube.

The original trailer for Left 4 Dead 2. You won't see any of these folks in The Sacrifice, but you will see those zombies.

Left 4 Dead 'The Sacrifice' Visual Guide

The accompanying digital comic for The Sacrifice serves as a great, story-expanding complement to the expansion, fleshing out the history of Bill, Francis, Louis and Zoey.