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