I haven't had a lot of time to play Orthanc this week, as I've been furiously prepping my novel for NaNoWriMo. And, you know, playing The Legend of Zelda: Twilight Princess. I can't write all the time, you know. I did manage to squeeze in a few hours of old-school gaming, though I wouldn't say that my progress was all that positive.
The most important discovery I made about Orthanc is that the dungeon is not purely linear. Stairs going down from level 1 don't necessarily lead to level 2. So, whereas I thought the level that I'd been exploring was level 2, it was actually level 3. I discovered this when I found a new set of stairs leading down from level 1, and ran into a mapping discrepancy. Alas, about the time I did discover it I ran into a Werewolf, and was promptly eviscerated; my Magic Missile spell wasn't enough to stop it.
So now when I use a new set of stairs, I also cast a Depth spell to figure out what level I'm on. Orthanc has a good selection of non-combat spells, albeit ones culled pretty heavily from D&D. The aforementioned Depth tells you what dungeon level you're on. There are a couple of Cure spells of different levels, a Levitation spell to avoid pits and chutes, and a Light spell to reveal secret doors. There's a Find Traps spell, though I've yet to encounter any traps just yet. There are a whole bunch of spells I haven't tried yet, though some of them seem self-explanatory: Speed, Protection, ESP, Passwall, Pass Ceiling, Pass Floor, Invisibility. I'll do some experimentation and get back to you.
I had a lucky break with my next character, as I found two stashes of gems that quickly got me up to 4th level. Treasure provides XP when you haul it out of the dungeon. There isn't a lot of variety: just coins of varying values (copper, silver, gold, platinum), and gems. Gems can be worth a lot, and are the best ticket to gaining levels. Carrying treasure adds to your weight, though I haven't figured out what effect this has. Perhaps an increase in monster encounters?
Anyway, my current character's luck hasn't exactly held true. While exploring level 2 I fell through a chute and ended up on level 4. Then, while frantically looking for some stairs I fell down a pit to level 6. Currently I'm trapped on level 6 with not much spell power or hit points. It's going to take miracle for me to escape, but I'm about to take a crack at it. Wish me luck!
Postscript: I got murdered by a Dwarf without ever finding my way out of level 6. If there's an upside to this scenario, it's that I got a good amount of levels 6 and 4 mapped out. Huzzah for mapping!