Infiltrator Class

Summary
Infiltrators, alternatively known as fast zombies, are the only class able to climb through windows to enter buildings. This gives infiltrators a unique advantage in being able to completely bypass doors and get access to the tasty harmanz hiding inside.

Playstyle
Fasts are great for individual play because of the easy (easier) access to humans. Fasts also make useful scouts. However, the initial levelling can be rough due to high failure rates on climbs. Once an infiltrator has reached a decent climbing skill level, then they're pretty much set until zombies have destroyed most of the map. At that point, humans go into hiding in ruined buildings and fast zombies have no additional benefits over other zombie classes. Ruined buildings don't have doors to keep zombies out.