I've been playing Nethack for a little while, and I'd like to try SLASH'EM. I understand there is a lot of new stuff in SLASH'EM - magic, items, monsters, classes, etc. I've also heard that it's considerably harder!
What I'm wondering is what unexpected dangers exist in SLASH'EM, but not Nethack - stuff that is different in a way that's liable to kill me without warning. (Also, if there are any new advantages I can abuse - a super-Elbereth or something - that'd be nice to know about too.)