Here is the full list of all 15 Invasion: Brain Craving achievements.
Defeated 150 Unholy Dead!
Defeated 100 Unholy Dead!
Defeated 50 Unholy Dead!
Recruited Aisha.
Recruited Doc Brown. Now if only we could go back in time!
Awoooo! Awoooo! Defeated the Werecar miniboss.
Defeated 10 Unholy Dead!
Recruited Jeth.
Recruited Clarissa.
Rerolled your game!
Recruited Red. .... ..... ....... ....
Recruited Blue. Ga-ry, Ga-ry, Ga-ry!
Recruited Peach. She was in this castle all along, hero.
Defeated your first Unholy Dead!
Enter Post-Apocalyptia