It somewhat depends on style I think. For example, see the last JADE thread on here, and various entries in Biskup's blog as he tackled it, where the lack of a clean full-screen option was lamented alongside then laggy performance as the ADOM people really went for the immersion on it.
Heh, even for the people constantly referring to Wikis and whatnot when playing---I'd bet some of them are running it dual monitor.
Safest bet is generally to open up the game to a main title screen after perhaps a very short intro, to where they can set and save all manner of preferred settings ingame and before actually starting with creation and moving around and such. Windowed versus Full Screen can also make a difference for people intending to record the game depending on their set-up as opposed to just personally playing.
Also, actually from me: What is the difference between the difficulty levels? A little summary next to each level would be educational and perhaps spur some ideas outright as there's a few different ways it can be gone about----like the worst way being ToME 4's Insane mode. If donations pick up for the project it might be nicest of all to have that screen more visual with actual large medals alongside their tooltips and whatnot as opposed to just the short listing.