i don't quite understand infinite corridor and crimson shroud, they take so long to "walk to" how are they ever worth it.
First off, there's an Arcane Card that pulls all items to you on the level every few minutes. That way you can get them all immediately.
Generally if you have about 15 mins left you can easily level every item just walking to them. I've done it for Shroud and Corridor past the 20 min mark many times, but you need to level quickly if you try that.
Both are needed to kill death, required. Corridor will do 8-10x damage of anything else in the end, even if you get it late. It's that powerful.
Plus, if you wait till all your weapon and item slots are filled you can pick up all the level items as bonus items far past what you can carry.