You start as Isaac with one item: The Moving Box. You start with one card: The Credit Card. There is one rule: Do not take any items, consumables, hearts, batteries, keys, bombs, coins, NOTHING. All things you want to pick up must be stored in the moving box, once you get to the next floor, ONLY THEN may you open the box and collect what's inside. Until then, you may pack and unpack as many times as you like, just as long as you do not pick up anything you find in that floor. You can get rid of your space bar item, but keep in mind that it is your ONLY source of any items and consumables. Your goal is to defeat the last boss you can get to. (If you get the key pieces: Mega Stan, if you get the void portal: Delirium, etc..)