Here is the full list of all 28 Ben 10: Power Trip achievements.
Defeat Hex and Save Strudelbek
Find the Omni-Guard
Defeat the Forest Power Spring
Unlock Four Arms
Fast travel using the Rust Bucket
Defeat the Mountain Power Spring
Unlock Diamondhead
Unlock Rath
Defeat the City Power Spring
Unlock Shockrock
Unlock XLR8
Complete your first Side Mission
Defeat your first Void Ruin
Choose your first upgrade
Unlock Heatblast
Destroy 5 Decibel Concerts
Destroy 10 Decibel Concerts
Destroy All Decibel Concerts
Complete everything in Grashugel Forest
Complete everything in Strudelbek City
Complete everything in Mt. Eisburg
Collect all the Records
Save all the citizens from monsters.
Find all the Trinkets
Complete all the Scooter Challenges.
Find all the Power Upgrades
Find all the Luck Upgrades
Find all the Toughness Upgrades