One person

[Caelum]

Now I know that if you do a special something you have to go the dungeon alone after the first play through.

however I am curious is how one can set up the game where it is just...you and no other party members. And aside from that, any "challenges" which involve just one party member?

[igortroy]

it's called "Toorum mode". he's the guy who's been leaving all those notes you saw in your 1st playthrough. sadly, he's met a terrible fate somewhere in the Temple's level 2. it's a secret room where you'll find his skeleton and some very nice gear. bring the skeleton to a savepoint crystal and just drop it in.
now, start a new game and in character generation screen just write Toorum and press enter.
you'll start the game playing as Toorum in a party of one.
he's a Ranger so he can both fight and cast spells, plus he moves really fast. very fun, and a very nice bonus to Grimrock in my opinion.

http://www.gamebanshee.com/legendofgrimrock/walkthrough/toorummode.php

[DariusOne]

If you missed Toorum on your first playthrough and don´t happen to have a good save, you can always very simply cheat it in:

http://www.cheathappens.com/show_board2.asp?headID=112363&titleID=18707

[Caelum]

Cool, thanks you guys!