Description Hidden Source is a multiplayer mod for Half-Life 2 created by Hidden Team. Players choose the role of either a near invisible killer, Subject 617, or one member of an Intercept squad who have to capture him, I.R.I.S. In the simple but challenging gameplay of an 'one against all' mode, Subject 617 creeps/sneaks through the maps armed only with a knife and three pipe bombs. The IRIS team carry a selection of weaponry, fully customisable at round start, from F2000 assault rifles through to shotguns or sub machine guns as well as a pistol as a secondary weapon.
However, they can hardly see Subject 617 as, just like the 'Predator', only the outline of his silhouette is visible. On top of that the Hidden also moves a little faster and has many abilites such as pouncing, wall grabbing, corpse pinning and the fatal pigsticker attack. Therefore co-operation is necessary for I.R.I.S. if they wish to prevail (if they dont want to become the prey/victim themselves).
This leads to an outstanding gaming experience on public servers: The I.R.I.S team creep/sneak through the corridors, back to back & covering each other whilst Subject 617 lurks in dark corners choosing his time to attack. The player who finally kills the Hidden takes over the role & from then on he can roam like a ghost through the corridors.