Deus Ex's gameplay combines elements of the first-person shooter with stealth elements, adventure, and role-playing genres, allowing for its tasks and missions to be completed in a variety of ways, which in turn lead to differing outcomes. Presented from the first-person perspective, the player can customize Denton's various abilities such as weapon skills or lockpicking, increasing his effectiveness in these areas; this opens up different avenues of exploration and methods of interacting with or manipulating other characters. The player can complete side missions away from the primary storyline by moving freely around the available areas, which can reward the player with experience points to upgrade abilities and alternative ways to tackle main missions.