Here is the full list of all 24 Rooster Teeth vs Zombiens achievements.
Rescue your first cast member.
Craft your first defense/trap.
Kill a Zombien with every weapon in the game.
Survive 10 Zombien waves.
Survive 20 Zombien waves.
Survive 30 Zombien waves.
Survive 50 Zombien waves.
Get the player character to level 10.
Get the player character to level 20.
Kill 50 grunts in a single session.
Kill 30 brains in a single session.
Kill 10 brutes in a single sesion.
Kill 20 kamizombiens before they explode in a single session.
Kill 25 militia zombiens in a single session.
Kill 15 plague carriers in a single session.
Recruit a full party.
Have 15+ of each resource at a given time.
Craft 20 traps/defenses in a single session.
Accumulate a 10x multiplier.
Kill multiple enemies with a single trap.
Build 10 defenses in a single session.
Build 10 traps in a single session.
Reach first place in a Daily Challenge leaderboard.
Purchase every weapon in the game.