Unlike the first two types of missions, which can only be done one at a time, the player can run four different World missions concurrently. World missions are generic tasks which offer lesser rewards, but are far more numerous to compensate. Guide missions are special tasks done on the behalf of the guide character, typically offering the best equipment available as a reward. A meter encircling the mini map called the fusion matter meter shows the player's progress in this regard. Nano missions are granted automatically once the player gathers enough fusion matter but now you get the mission from the character fought or gotten. Missions come in three types: Nano missions, Guide missions, and World missions.
Missions are given by various Cartoon Network characters around the game world, who usually cluster around travel hubs. The main focus of the game is the completion of missions. The player can switch between guides if they choose at a guide changer. After leaving the first level, they can choose between four guides: Ben Tennyson, Edd ,Mojo Jojo, and Dexter. The player is guided in their quest by a specific character, beginning with Dexter's computer, Computress. Instead, they gather a loose analog known as fusion matter (which has multiple purposes) through defeating enemies and completing missions, and upon collecting enough can perform a mission to raise their level, but as of February 16, fusion matter acts more like experience as players can now perform multiple nano missions every four levels.
Unlike ordinary role play games, the player does not gain experience in the conventional sense. The player is provided with various weapons to accomplish this, including ranged and melee weapons. Gameplay primarily focuses on accomplishing missions. The game has large playable environments, with travel facilitated by various warp points. Their character is viewed from a third person perspective, viewing the HUD, and the range of movement consists of walking in any direction and a short-distance jump.
In Fusionfall, the player takes control of a customized avatar.