Fusion is a team-vs-team, arena-style game. The score is represented by a bar across the top of each player's screen, which starts as half blue and half red. As each player earns points for their team, that bar fills more with their color, creating a sort of Tug-of-War style scoring system. The team that fills the bar with their color wins.

Team configurations have no limitations. The game is specifically designed to allow any mix of teams to not only be balanced, but also to feel fully engaged. A match between 4 Soldiers and 4 Hackers is a fair fight and is full of direct interactions and strategies.

In addition to specific mode-to-mode interactions, Fusion has an overarching team inventory system. Each mode has the ability to collect items, which become a part of their team's inventory. Items are mode-specific and any team member of the appropriate mode can use any item. This enables team members to fall back into a supporting item-collecting role to assist teammates in a better position ot score points or cripple the opponents.