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