Binding of Isaac: Rebirth - The Lost runs completed!

I've completed what is supposedly the "hardest" challenge in The Binding of Isaac: Rebirth, beating all the routes with the character "The Lost". Proof below.

The Lost is a strange character who requires a rather convoluted method to unlock. His unique attribute is that he dies in ONE HIT. His hearts cannot be extended in any way and the only way to extend  his life is through certain powerups like Holy Mantle, which allows him to take two hits in a room before croaking.

Moreover, the "Exit Game and Backup Save" technique to create checkpoints will NOT work with The Lost, as leaving the game session and then returning will cause him to instantly die.

Unlocking everything requires you to clear the game at least twice with The Lost. One unlock requires reaching a certain point on Hard Mode. Scared yet?

Actually, it wasn't as hard as most people were saying. I'm guessing they haven't played the game enough to get really good at it. I can honestly say I've done much harder challenges than finishing the game with The Lost :) There are just too many tricks in this game to abuse that make the game easy to clear, even with a character who dies in one hit.