Here is the full list of all 35 Droid Assault achievements.
Defeated Level 10 Boss
Defeated Level 20 Boss
Defeated Level 30 Boss
Defeated Level 40 Boss
Completed Arcade Missions
Got Red Alert status
Achieved security level 2
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
Command a full squad of 8 droids
Buffed a droid in every aspect
Maximum Armour buff
Maximum Damage buff
Fried 100 robots
Crushed 25 robots in doors
Defeated a boss with only a Sec Level 1 droid remaining
Achieved security level 1
Got Red Alert twice on one level
Captured the Ultimate Droid
8 droids in ascending security order
Captured 3 9-series robots in same squad
Maximum Recharge buff
Maximum Battery buff
Maximum Overdrive 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
Destroyed 100 robots with the disruptor
Started a level with 8 droids, finished with only 1