 Once the player has completed a mission on a planet, they can typically return to any previous planet they have visited to attempt missions they could not complete before.In addition to objectives based on platforming and weapon elements, missions may include minigames such as various races and arena combat.Typically, one or two of these minigames must be performed as part of the main story, but further optional challenges can be done to earn greater rewards, typically in the form of "bolts", the unit of currency used throughout the game.