Plot

At the start of the game, a mosquito-like drone extracts much of the DNA from the Omnitrix, leaving only Heatblast and Fourarms on the watch. While at the Grand Canyon, he battles Vilgax's drones and after defeating an army of them he gets sees a pieceof the Omnitrix. With it, he regains XLR8.

Ben later finds Vilgax's drones and the Forever Knights fighting at Mesa Verde, and Ben decides to battle them both. After defeating them he moves on to Area 51, where he finds Enoch, who he defeats, but Enoch has built a giant robot that Ben battles at Hoover Dam. After defeating the robot he regains Cannonbolt.

In San Francisco, Ben find out that Kevin escaped the Null Void, and he learns to use Cannonbolt to battle Vilgax's drones, and later on Gwen tells him Kevin escaped and ran into the Redwood Forest, and Grandpa Max ran in after him. They find some Spug Au Gratin at Crater Lake later on, the same place they battle Kevin, then a Null Void portal comes out of nowhere and it pulls him in. Then they figure out ,that there are some plants attacking the Seattle Space Needle.

When Ben arrives at the Needle, the motherplant has already infected it. After Ben defeats it, he gains Wildvine, leading to finding out Animo has gained his DNA to create a mutant army. At the same time, in space, Vilgax sends Zs'Skayr down to Earth to attack Ben.

At Effigy Mounds, Ben battles Hexlord along with some Loboans, Thep Khufans, and Transylians. At this place, Zs'Skayr finds Ben, leading them to Mt. Rushmore to check some some stuff out. Later on at the Navy Pier Ben faces Zs'Skayr and defeats him. At the Historic Battlefield, Ben battles Animo's DNA mutants, and Animo kidnaps Gwen. Then, at a bayou, they battle Clancy in human form, he works for Animo. After this at the Oil Refinery, Ben defeats Animo. Gwen finds out he works for Vilgax and that Vilgax is planning to suck the entire planet into the Null Void.

They arrive at Washington D.C. to warn the government, where Ben battles Vilgax's drones again, accept they are remodified. Then, they decide to try to blast into the Chimerian Hammer, and it is easy since Max used to be part of NASA. At Cape Canaveral, Ben defeats Sixsix as they go into the Chimerian Hammer to defeat Vilgax. After this event, they go to the Null Void to battle the bosses again.

Gameplay
In the beginning, Ben can stay an alien for a limited amount of time, but after defeating some bosses, Ben unlocks more powers for his aliens and even unlocks the master code, meaning he can stay alien for an infinite amount of time or switch between aliens without draining Omnitrix energy. Attack combos can be unlocked collecting Omnitrix points. Limited power boosts or invincibility can be gathered, as well as bonuses to make the Omnitrix recharge faster. Three Sumo Slammer cards are hidden in each main level, and once collected unlock features, such as movie clips.
After each level, Plumber ranks are rewarded, depending on how fast the player beats that level. If the player gets an A rank, you get a character view, usually a boss or a villan. In the main boss levels, a God of War styled button sequence allows players to execute a special attack at certain points.

Bosses

The Super Droid is the very first boss battle. It will act very similar to the attacks of Enoch's giant robot, using it's arms to hit Ben.
Ghostfreak- Ghostfreak takes over other peoples bodys to fight. He first takes over a Fangface. After knocking the Fangface out, use Wildfine too pull the curtain open, causing light too hit Ghostfreak. After that, Ghostfreak will use a Mummy, then a Viktor. After finishing them, Ghostfreak will escape to the basement. Use the knight shields to reflect the light too Ghostfreak. Now you will fight Ghostfreak. After beating him, you will get a new crystal!
Enoch- Enoch uses a sword for his attacks. He can slash, he can even make a big explosion. Enoch will escape after you defeat him, now he will try too destroy you at Hoover dam with his big, Enoch robot.
Enoch robot- A robot version of Enoch, appears at Hoover dam too try and destroy Ben. After the fight, you will get a new alien.
Clancy- A man who uses bugs to attack. He appears in Bayou running from Ben and Grandpa. He eventually is chased into a cave where you must fight him. Clancy will use Wasps to attack, just dodge the shape-shifting he does.
Vilgax- In the level next to the last, you will fight Vilgax. At first Vilgax will use a machine too make him bigger. Start attacking Vilgax and he will soon shrink to normal. Now Vilgax will start punching you with health-taking punches. He also uses a whip, when Vilgax laughs it means he's going too use the whip. Now, after fighting Vilgax and playing the action-mini-game, Vilgax will start flying, use Cannonbolt on the ramps to make Vilgax fall. After doing this and playing the mini-game, Vilgax will fly and shoot a laser that makes the floor electricute Ben. Use Wildvine and knock Vilgax down. Now play the last mini-game and Vilgax will get sucked into space! He next will get sucked into the Null Void.
Giant plant- This plant is a giant enemy and can be stunned by hitting the balls around it. After hitting the balls, use Cannonbolt on the ramps.
Dr. Animo- Dr. Animo appears at the Oil Refinery. He uses hard punches on Ben for his attacks.

Other Information

Playable Characters

Ben Tennyson

Fourarms

Heatblast

XLR8

Cannonbolt

Wildvine

Diamondhead

Upchuck (DS Version)

Enemies

Southwest

Vilgax's Robots

• Green Drone
• Forever Nights
• Enochs Robot
• Forever Champion
• Forever Champion Elite
• Enoch
• Vilgax's Protect Robot

Northwest

• Vilgax's Robot
• Thornhound
• Thornhound Agressor
• Kevin 11
• Thornhound Charger
• Maceroot
• Motherplant

Midwest

• Fangface
• Fangface Howler
• Mummy
• Cyclone Mummy
• Hex
• Vilgax's Robot
• Viktor
• Ghostfreak

Southeast

• Snakefly
• Felicine
• Clancy
• Crystalclaw
• Dr. Animo

East Coast

• Vilgax's Robot
• Vulcanus
• Six Six
• Vilgax
• Forest Mutant
• Wildvine Mutant
• Cyclone Mummy
• Viktor
• Crystalclaw