This mod harks back to a bygone age, when innovation with first person shooters was king. Games like Thief, Requiem or Shogo would explore new approaches to the shooter genre. Substance sought to merge the different playstyles into a precursor to the Crysis suit. Each of the HEV Suit Modes comes with its own weapons and abilities, like energy shields or cloaking. Just like multiplayer classes, which can be switched on-the-fly and share one gigantic inventory.