<Idea> easy to add game content: Producing hearts is a huge portion of the game and It is handled by only one baby (lil C.H.A.D.).
Most probably you can double the resulting game content (the game content doesn’t double but playing styles double) just by adding new unique ways for producing hearts. For an example if there was a baby that produces much heart by summoning an enemy it would been a totally new type of playing the game which means you easily doubled the resulting game content.
Unique heart producing baby Ideas by me: a baby that summons an enemy and produces a huge amount of heart, a baby that produces hearts when enemies die, a baby that instantly produces a huge amount heart and dies, a baby that produces heart when it takes damage, a baby that produces heart by damaging enemies. Thanks for reading. I trust you.