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