Here is the full list of all 21 Warpips achievements.
Kill 500 enemies with Small Turrets
Complete Endless Mode with at least 50k points
Win the campaign on General difficulty
Spawn 200 Vehicles
Marines fire 1500 grenades
Beat the third island in the campaign
Kill 150 enemies with Missiles
Shield Pip takes 4000 damage
Mine $5,000 cash from Pumpjacks or Oil Derricks
LRV spawns Marines 50 times
Beat Conquest Mode on any difficulty
Complete Endless Mode with at least 100k points
Beat the second island in the campaign
Complete Endless Mode with at least 150k points
Spawn 2000 Infantry
Sniper kills 100 enemies
Call in 150 Tactician artillery strikes
Spawn 35 Spec Ops Pips
Complete the tutorial.
Beat the first island in the campaign
Capture every territory in the campaign