Exo Suits
To unlock the Exo Suit, progress through the main story until you leave Willamette Memorial Megaplex and reach Old Town. While in Old Town, the Exo Suit will become available. To get more Exo Suits, find the caches marked "Exo Suit" scattered throughout the game. The caches can also be in other supply crates or just lying on the ground in corners. To easily find an Exo Suit, look for large shipping containers guarded by Obscuris mercenaries since those containers usually have an Exo Suit cache in them. The battery in an Exo Suit only lasts two minutes. An Exo Suit basically allows you to easily kills zombies while being invincible and having unlimited stamina. Additionally, some interactions are only possible with an Exo Suit, which provide unconventional weapons for the Exo Suit that can be further enhanced by collecting ammunition crates for power-ups, such as guns and missiles.