Here is the full list of all 67 Ultratron achievements.
Defeated Letum
Got 100% on a dodge stage
Killed 100 enemies with grenades
Defeated Lues
EMP shocked 25 enemies in one blast
10 kills with a single grenade
Upgraded rocket pet to maximum
Maxed turbo power and recharge
EMP shocked 10 enemies in one blast
Full complement of smartbombs
Maximum droid power
Maximum dot slurp range
Upgraded shooty pet to maximum
Upgraded laser pet to maximum
Upgraded all pets to maximum parameters
Maximum drone upgrades
Grenade add-on upgrades maxed
Maximum shields
Defeated Bellum
Got 100% on a challenge stage
Held one or more pets for 5 levels without dropping
Collected 1000 dots
Smartbombed 25 enemies with one blast
Collected 10 fruits
Consumed 10 consecutive fruits
Vanquished 1000 enemies
Defeated Ieiunitas
Collected 500 dots
Vanquished 500 enemies
Smartbombed 10 enemies with one blast
Maximum score multiplier
Collected 250 dots
Player has fired 1000 shots in a game
Collected 100 dots
Vanquished 100 enemies
Defeated two bosses
Detonated 25 smartbombs in a single game
Vanquished 2500 enemies
Vanquished 5000 enemies
Vanquished 10000 enemies
Collected 25 fruits
Collected 50 fruits
20 kills with a single grenade
30 kills with a single grenade
Killed 500 enemies with grenades
Killed 1000 enemies with grenades
Shooty pet levelled up to maximum
Laser pet levelled up to maximum
Rocket pet levelled up to maximum
Drone survived 10 levels
Drone survived 20 levels
Drone survived 30 levels
Awesome double three way bouncy gun
Double three way bouncy bezerk gun
Double three way bouncy max power rapid fire gun
Survived assault level without taking damage
Single drone shot down 100 enemy bullets
Single drone vanquished 250 enemies
Player has fired 10000 shots in a game
Player has fired 100000 shots in a game
Beat a level without firing a single shot
Detonated 10 bombfruits
Smartbombed 50 enemies with one blast
EMP shocked 50 enemies in one blast
Quantum-shifted through a boss
Held one or more pets for 10 levels without dropping
Held one or more pets for 20 levels without dropping