It is frustrating if you're used to modern comforts. Wizardry 5 used that technique quite a bit - there's a locked door, so shouldn't there be something worth locking it for? The mapping was frustrating for me, I love games with an auto-map that you can bring up anytime.
I'm currently playing Wizardry: Tale of the Forsaken Land on PS2 and having some frustration with the fact that my created party rocks but if I don't add the game's plotline characters to my party then I lose content. What blows is that the plotline characters can't change classes in the traditional way (you have to force them by using items that cause class change) so they're gimped as far as cross-training skills. And there's more than enough of these characters to make your entire party, which I feel is a gimmicky way to get "replayability" by not allowing you all the content in one playthrough.
I believe once you enter that floor
You go into an area of darkness. There is a door in a straight direction from the stairs (I want to say South?), not hidden (other than the darkness), just keep using the bottom move action when you hit a wall. Once you go through that door you will be out of the darkness.
Edit: Aside from my gripe, Tale of the Forsaken Land is turning out to be a decent old-school Wizardry. It almost
gets too far into anime graphics for my tastes, the overall plot is bleh, but there are many subplots and sidequests to follow. I'm hooked, gotta finish it - and then there's postgame content!