In the game, the player participates in Custom Robo tournaments and tries to earn money to buy parts to use to improve their robo.
Fights start with the opponent's robo customization being shown. The player then may make adjustments to his or her robo—such as changing parts, polishing, and altering the diorama. This can also be done outside of a battle, in the portable garage.
Battles begin with the player's custom robo cube being launched out of a Robocannon(controlled with the D-pad). There are six sides of the cube on which the robo can land.
The objective of the battle is to reduce the opponent's energy points from 1000 to 0 by using the player's guns, bombs, pods, and dash attacks. There are two third-person views in battle and five different control schemes.
If the player repeatedly loses the same battle, the game offers the option of a health handicap, which goes up to 75%. Each victory increases the player's Soulboost meter and when it is full, Soulboost can be used. Soulboost makes the robo stronger and tougher for about 21 seconds, afterward making the robo weaker for a short time.
Source: Wikipedia, "Custom Robo Arena", available under the CC-BY-SA License.