Here is the full list of all 12 Talent Not Included achievements.
Complete the Forest act.
Complete a boss scene with full health.
Complete a scene in co-op mode with both players at full health.
Complete a scene in co-op mode.
Kill 50 enemies with the Warrior.
Kill all the enemies in a scene.
Take 8 damage in a single scene without dying.
Complete a scene with one heart left.
Kill the final boss.
Complete the Desert act.
Complete the Winter act.
Get all the masks in the game.