Here is the full list of all 15 Rage Wars achievements.
Collect 5000 potatoes in game
Unlock laser in store
Do 100 killstreak chain 10 times
Unlock flame thrower in store
Kill last boss
Go in rage mode 200 times
Unlock chainsaw in store
Complete World 2
Unlock rifle in store
Kill total of 1000 zombies in game
Do 50 killstreaks in game
Unlock Rocket launcher in store
Complete World 1
Unlock Shotgun in store
Unlock game rage faces in store