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