Here is the full list of all 38 Ben 10 achievements.
Defeat the Weatherhead Prime without taking damage
Reach the top of the Weatherhead Tower without falling off
Collect every Sumo Slammer card
Dodge Weatherhead lightning, then hit the attacking enemy by using Upgrade’s ability
Complete ‘The Hive’ in under 15 minutes
Defeat Queen Bee without taking damage
Complete ‘The Scrapyard’ in under 15 minutes
Stun a self-destructing Bumblebee with Stinkfly’s ability
Hit 5 enemies with a single rolling Tweedledee
Defeat 3 enemies with a single Four Arms throw
Defeat a Pie Juggler before their pie hits the ground with XLR8’s ability
Completely upgrade all aliens
Complete ‘The Funhouse’ in under 15 minutes
Defeat Zombozo without taking damage
Destroy 5 objects with a thrown enemy
Defeat an enemy as each of the 10 aliens in one fight
Complete “The City” in under 15 minutes
Complete ‘The Tornado’ in under 15 minutes
Finish the game
Complete ‘The Canyon’ in under 15 minutes
Hit 10 enemies with a single use of Diamondhead's ability
Defeat 2 enemies with a Weatherhead Drone
Collect half of the Sumo Slammer cards
Defeat Queen Bee
Cause a chain reaction of 5 exploding Bumblebees
Defeat 6 enemies with a single Cannonbolt roll
Complete 30 Bonus Objectives
Defeat 3 enemies with a single use of Overflow’s ability
Defeat Zombozo
Hit 5 different enemies with a single shot from Grey Matter
Defeat 3 enemies with a single use of Heatblast’s ability
Defeat 5 enemies with a single use of Wildvine’s ability
Achieve a combo of 100
Completely upgrade one alien
Defeat 10 enemies as Ben
Collect a Sumo Slammer card
Defeat 10 enemies with a single Ultimate Ability
Achieve a combo of 50