I've played only one run of this. I lasted longer than I expected to. Perhaps longer than I should've.
People in the comments aren't kidding when they say this game is brutal, not just mechanically, but psychologically. One slip-up can leave you with a wound you'll be dealing with for the rest of your short life, and the screen effects and the character's dialogue make sure that you know exactly how much pain he's in.
I made it to layer 3, but I was probably already doomed by then. His whole leg was infected, and by the time I found something to treat it, all it could do was slow it down. My little fluffy dog guy died slowly, lying in some sandy pit, trying to claw himself to death before the sepsis and starvation could beat him to it. There was nothing I could do but watch. There was a part of me that hoped he might die during the times he passed out from exhaustion, because he was in too much pain to sleep. He didn't get that mercy.
This is a very good game. I don't know if I have it in me to play a second run.