Knowledge is what matters the most in Isaac compared to most roguelites and roguelikes.

Fucc, I messed up getting further into the devil pits. I mistakenly left the room.

I don't know why I keep only fighting mom's heart. Where's the devil and angel from before?

They succeded in making it much harder, I'd say that much. I beat Afterbirth & Afterbirth+ over a dozen times yet only managed to beat this about 3 so far and I started a clean slate.

It is still varied in terms of pick ups and more varied in terms of bosses but it seems that you're far less likely to find those OP power combos like before.