Ben Alien Force Battle

For the most part, gameplay across the seven included worlds is a balance of action and puzzle-solving that revolves around the skills of Ben Alien Force Battle forms. Ben might need to change into his Humungousaur form to break through doors, or use his Swampfire form to ignite flammable substances. Each form has different combinations and special attacks that it can execute, and Ben can unlock new abilities by defeating enemies and collecting glowing energy orbs.

However, there is one gameplay element that players should be aware of: using a form's innate abilities drains energy from Ben's Omnitrix meter, preventing them from continually being used until the meter can recharge. As a result, players will need to focus on combos and save their special attacks for finishing blows instead of constantly wielding them in battle.

The story starts as Vilgax invades Bellwood with a gigantic Null Void Projector, releasing hundreds of Null Void prisoners into the city. Ben attempts to transform into Alien X, but Professor Paradox stops him, stating that now is not the right time to use Alien X. Instead, they split up to tackle the invasion. Ben fights his way to Psyphon (who's coordinating the attack from ground level), but when Ben defeats Psyphon, he brings to life a Mr. Smoothy sign as a distraction.

Ben defeats Mr. Smoothy by quickly hitting it with every alien in his arsenal, except for Cannonbolt and Alien X, and in the process puts the Omnitrix into reboot mode and locks out most of his arsenal. Azmuth appears on Ben's shoulder and examines the Omnitrix, saying that it needs to recharge before Ben can access all aliens again. To make matters worse, Professor Paradox informs the the team that Vilgax has successfully taken over Earth, so he sends them back far enough in time to destroy every power source for his Null Void Projector possible in the whole galaxy, stating that the first is being recycled from the toxic radioactive waste of Vulpin: Wildmutt's home planet, however only Spidermonkey, Big Chill, Humungousaur, Swampfire, and Cannonbolt are available. (Only Swampfire and Goop are available in the DS version).

Arriving on Vulpin, Ben orders Gwen, Kevin, and Ship to stay put, because if Vilgax arrives, it will take all of them combined to hold him off. Ben fights his way throughout the refinery, going through Vilgax's bioids, the local Vulpimancer, and a giant two-headed snake. Ben then finds the Vreedle Brothers (Darkstar replaces the Vreedle Brothers in the DS version) and manages to defeat them. Then, Ben finds a holographic message from Max, stating that the one Ben destroyed isn't the only one, and responds that he's currently on his way to Terradino: Humungousaur's home planet, to destroy the energy core there. Goop is then unlocked.