The Seed of Evil Add-on for Mutant Year Zero: Road to Eden has 17 achievements worth 460 gamerscore.
Defeat the demon-tree Jyko.
Complete all of Pripp's side-missions.
Collect every artifact in the Zone.
Collect every type of hat in the Zone.
Stand under a Bus Stop with Big Khan in your party for 110 seconds.
Collect 600 scrap.
Put Goran out of his misery.
Catch up to the Elder.
Collect all notes in the Zone.
Convince Big Khan to join your crew.
Hit 3 enemies at once with Big Khan's Ground Pound.
Turn 3 enemies at once into cover.
Kill 3 enemies in a row whilst invisible.
Complete the SEED OF EVIL without using medkits.
Complete the SEED OF EVIL in IRON MUTANT mode.
Destroy 5 Pod Spawners before they release new enemies.
Find the secret room were the Ancients used to meet.