Is there like a very good unit for this that makes the challenge a cakewalk or what babies would you guys recomend? It seems pretty impossible

I managed to do it, it was real hard but I had a good combination of familiars and items.

First off, Glowing Hourglass is absolutely super duper busted so if you get that, you should be mostly fine.

The Deserter is a powerful damage dealer that's useful in levels that don't contain Hardheads or Hardies.

Straight shooters are usually best since lobbed-shots really just don't matter unless Plums are a pain in the ass or you want to use Spider Baby.

Spike baby and Tooth and Nail are real effective, especially with Sanguine Bond which helps you generate more hearts without C.H.A.D.s

That's about all I have for general stuff. I had Telepathy for Dummies and Monster Manual as my actives during my run.