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