Rocket Arena is a 3v3 competitive multiplayer game played from a third-person perspective. At launch, the game features 10 maps and 10 playable characters, each of whom have different abilities. The player's main weapon is a rocket launcher, though there are items that the players can pick up in the arena. The game does not feature a health system and instead relies a system named Blast Meter. Whenever a player is hit by a rocket, their blast meter will fill up. A player with a full blast meter, when being hit by a rocket, will ricochet and fly out of the map, resulting in death. The player character is very mobile and has the ability to dodge other rockets, triple jump, and rocket jumping.
The game is released with 5 modes at launch: Knockout and Megarocket are variants to standard team deathmatch and Capture the Flag mode. Rocketball sees players attempting to blast a ball using rockets into another team's goal. In Treasure Hunt, a treasure chest will spawn in the middle of the map and once a player picks up the chest, their teammates need to defend them so that the chest would not be stolen by other players. The game also features a cooperative multiplayer mode named Rocketbot Attack in which three players fend off waves of bots controlled by artificial intelligence.