Torches don't count down when the game is paused. They would when you sleep, but they are automatically snuffed out. The timing currently about half what you say it should be. I'll check what the original does and tweak it to match.
Yes, all the combinations from Underworld should work, including stick + oil.
The saves are zipped JSON so they should be easy enough to futz with. maxMana recomputes when you increase mana skill. maxHP doesn't properly recalculate if you fiddle with strength. it just increases by a delta if you level up. carryWeight recalculates every frame.
The shoulder slots only take light sources. Sorry about that.
Auto key usage... hmm... apparently I forgot to hook that option up to the feature in the game. Whoops! More testing required.
I could add a screen explaining the controls in the options menu.
But all this will have to wait until I'm done with the keyboard and mouse code.
Thanks for the feedback!