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