There's a good amount of ways to access areas/items before you're normally allowed to in this game.
- It's possible to reach Sheol without beating the game ten times either by using the "We Need To Go Deeper" item or taking the hatch in the (possible) Devil Room in the supposedly last stage. Rebirth allows you to use Angel Rooms to reach the Cathedral, and winning enough times can even let you reach the Chest/Dark Room and potentially Mega Satan before even unlocking It Lives.
- It's possible to get credit for beating the game as ??? long before you can even unlock him by using the Ankh, an item that gives you an extra life, at the cost of transforming you into ??? on respawn. The character otherwise requires more wins of the game to unlock than any other character (at least in earlier expansions), so getting the item and deliberately dying lets you get his completion marks earlier and easier than intended, since you don't have to be.
- In Repentance, provided you are lucky enough, it is technically possible to unlock up to 30 characters
out of 34 in your first Repentance run, (that is, EVERY CHARACTER except Lilith/Keeper and their Tainted counterparts).- Has now been achieved in practice, requiring just over 26 hours of your time and several other people to assist you. The game will sometimes glitch and possibly even randomly lock already unlocked characters, the item generation can ruin your run any time, but it can be done.
- Has now been achieved in practice
