Reelism is a tongue-in-cheek variation on the "invasion" gameplay. It offers large, wide-open maps in which random monsters and weapons will constantly spawn during themed rounds. The "reel" mechanism also provide other game-changing effects which can help or, usually, hinder the players. Everything is filled with homages to classic gaming, in-jokes, and all-around silliness. The extreme randomness of the mod makes the gameplay rather unpredictable, since it is possible to obtain extremely unfair combinations as well as ridiculously easy ones.