Residue Processing is the tenth chapter of Half-Life. It charts Gordon Freeman's evasion of the HECU after being left for dead in a waste-compactor at the end of the previous chapter (Apprehension). Progression through the area is ultimately linear, though the player can return to earlier maps in the sequence by opening previously locked doors. In some cases, such contra-flow travel is a punishment for failing a jumping puzzle.
Criticism
Residue Processing has classically divided opinion among Half-Life fans. Whilst the premise of Gordon Freeman's mid-game disarmament and temporary vulnerability has been taken as a symbol of Half-Life's superior design ingenuity and gameplay dynamic, the chapter has drawn criticism for pacing and design issues (despite being only four maps long). On the first count, it is felt that the gameplay of the chapter is simply a retread of the simple Xen-Creature combat of the early levels. On the later count, Residue Processing is felt to be a rather unrealistic area populated with levitating, gravity-defying conveyor belts and generic 'toxic-green' sludge.
Trivia
Residue Processing consists of the maps c2a4, c2a4a, c2a4b and c2a4c.