UT was designed as an arena FPS, with head-to-head multiplayer deathmatches being the primary focus of the game. The game's single-player campaign is essentially a series of arena matches played with bots. For team matches, bots are again used to fill the roles of the player's teammates. Even on dedicated multiplayer servers, bots are sometimes used to pad out teams that are short on players.
UT is known and widely praised for its bot A.I., the product of programmer Steve Polge who had earlier risen to fame by designing the Reaper Bot for Quake, one of the earliest examples of an effective deathmatch bot. The player can choose a bot skill level (anywhere from "Novice" to "Godlike") or set it to automatically adjust to the player's performance. Bots can be further customized by changing names, appearance, accuracy, weapon preferences, awareness, and so forth.