Although beating the three chapters without lil CHADs is a pretty fun and difficult achievement, I feel that maybe it's a bit too much just to unlock a baby that just gives you twice as many hearts. Maybe it should've been an ingame 'challenge' where you just beat The Ark III without heart producers, that way it'd keep the challenge without forcing the player to go through the entire game.
Either that or buff Double Baby so that there's more of a reason to want to put so much effort on unlocking it.
I'm saying this because I lost right at The Ark III and i'm sad :(