1) You can beat Mom's Heart 9 times and get 9 different endings along with a new item unlock for each. After that, you can go on the next level(s) every time.
2) You get new items and achievements by beating the game with each character. Every time you complete a run for the first time with a new character, you unlock something.
3) There is 1 alternate boss to Satan and 2 more beyond him. You have to do some special things to get to them, yes.
4) Every time you complete a run, you get 1 Eden token.
Hope that helps!
Awesome, thanks!
One more thing:
You say beating the game with each character unlocks something.
Is it ok to beat the game only once with each character to unlock these items, or several runs are required?
Also, beating the game means beating Mom's Heart?
Is it ok to beat the game only once with each character to unlock these items, or several runs are required?
Also, beating the game means beating Mom's Heart?