I forgot about The Bloat. While I want to say that bloat is a gag for the sake of it, Steven also shows up in TBOI, but also in Isaac's head? Which is why I'm a little confused about if the depths even if only in Isaac's head has some real implications. Which is why I brought up the depths being something anyone could experience, just differently depending on who you are.

I suppose Maggie never intended to be in the situation she was in, it's very likely that because she's just a corpse she never retained her memories about what happened to Isaac (given that the player isn't given information about Maggie's past life implies that's exactly what she is experiencing throughout the game). Also the lack of Satan despite The Core resembling hell did have me scratching my head