Here is the full list of all 35 Droid Assault achievements.
Defeated a boss with only a Sec Level 1 droid remaining
Maxed every buff on a droid
Maximum Battery buff
Escaped with 0 hitpoints and no squad
Achieved security level 2
Defeated Level 40 Boss
Achieved security level 7
Achieved security level 5
Got Red Alert twice on one level
Defeated Level 30 Boss
Achieved security level 6
Maximum Overdrive buff
Flame, laser, and disruptor resistant droid
Defeated Level 20 Boss
Maximum Damage buff
Maximum Recharge buff
Got Red Alert status
Maximum Armour buff
Defeated Level 10 Boss
Achieved security level 3
Achieved security level 4
Buffed a droid in every aspect
Achieved security level 1
Completed Arcade Missions
Achieved security level 8
Achieved security level 9
Captured the Ultimate Droid
Command a full squad of 8 droids
8 droids in ascending security order
Captured 3 9-series robots in same squad
Everything-proof and maxed-buffs droid
Fried 100 robots
Crushed 25 robots in doors
Destroyed 100 robots with the disruptor
Started a level with 8 droids, finished with only 1