Left 4 Dead 2

Hailed as a genuine masterpiece and the true king of zombie games, it is praised for design built entirely around forced cooperation, where special infected punish lone-wolf play and reward communication. The AI Director's procedural pacing gives it enormous replay value, backed by tight, accessible mechanics, strong level design, audio cues, and a likable cast across both campaign and versus modes. Its main weakness is that the fun depends heavily on the teammates you play with.

Sequel maintains co-op zombie gameplay with 5 new campaigns, 4 new survivors, 3 new infected types, melee weapons.