Thanks!
You raise good points:
1: I had considered making the Obelisk's AP some kind of formula (e.g. AP=10 x [number of players]) or something, but after some consideration I decided that since there are ways to depower it, or freely run away, it works better as a serious threat if the players go in gung-ho without planning. I did playtest this, and my players defeated the Obelisk on the final round of combat. Interestingly they had two broken gadgets AND had interpreted the verses to mean ''obelisk is vulnerable to electricity', so they used the gadget as a club to chip into the Obelisk and then connected the power generator to it. I decided this would both deactivate the Obelisk as well as give them a d10dmg roll (times two hehehe) which blew it up.
However in the interest of finetuning the balance, I do think you are right and that I could hide a broken gadget in one of the rooms...
2: I think the roll tables will return an encounter with a cultist or trap (miasma, irradiated, vision or evil) three times vs two non-dangerous events. In my view this is enough for a one-session, but of course the warden is free to add *more* enemies or another npc scientist, who is driven near-mad but has survived to warn the players...
Cheers!