Aliens
As Ben, you can turn into any one of 10 different aliens. Each alien has specific strengths and abilities, so choosing the right alien for any given situation is critical. For instance, Swampfire is a master of fire, allowing you to attack enemies from a distance. Goop can constantly shape-shift and take out a group of enemies with combo attacks. Spidermonkey possesses remarkable speed and agility, giving you an advantage over slower enemies. Make sure to familiarize yourself with all 10 aliens.
Vilgax Minions
Vilgax employs an army of minions to do his bidding. You can defeat the basic Red Minions with a combo or a projectile attack. Shielded Red Minions can block projectiles, so you'll need to attack them from close range. Yellow Minions also possess excellent defense, making a rear assault or a heavy attack your best option. When encountering a Grey Soldier, perform quick melee attacks before he can call for assistance. Finally, to defeat Red Soldiers, unleash lots of combos and avoid their laser cannons, which fire three consecutive shots.
Ship
Once you complete a level, you have to fly Ben and his pals to the next planet via spaceship, fighting Vilgax's minions the entire time. You must complete the flying missions within three lives to advance to the next world. Pay close attention to your ship's energy level. You'll lose energy each time you shoot or teleport. If you run out of energy, you'll be unable to defend yourself, leaving you vulnerable to enemies. Be sure to gather upgrades and energy boosts from defeated foes to replenish supplies.
Mr. Smoothy
After clearing Earth Area 2, you'll have to defeat Mr. Smoothy, a giant milkshake. Transform into the alien Upchuck, who can gobble up attacks and spit them back at enemies. When Mr. Smoothy launches his projectile attacks, press X to block and Upchuck will eat the attack. Then press the A Button to shoot the energy back at Mr. Smoothy to inflict serious damage.
Darkstar
At the end of the Vulpin level, you'll encounter the villain boss, Darkstar. Change into the alien Goop and block Darkstar's initial attack. Then turn your attention to the red switch on the left wall. Attack the switch until it turns green. Move to the red switch on the right wall and do the same. Acid puddles will cover the floor. As Goop, you're immune to the acid, but Darkstar isn't so lucky. You can damage him only when he's in the acid.