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