Zork: Nemesis

Real-time:
*) get water before it evapourates (gallery room, Agrippa)
*) swinging off bell tower rope to balcony (monastery)
*) going through the wobbly door (asylum)
*) play crystals together (conservatory)
*) get thaddium into container (Irondune)
*) get thaddium container into tank (Irondune)
*) make iron before radiation kills you (Irondune)
*) use quintessence before alchemists complete their spell (Agrippa)

The bell rope requires a quick click, but you get to try it over and over,
and it only takes a few seconds per try -- it's not very hard.
The rest are very minor, but the last four are deadly if you fail.

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Relevance:
Irrelvant challenges:
*) constellation puzzle

There are a lot of machines. They fit the setting, but their relevance to
the plot is questionable.

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Difficulty:
The hardest challenges:
*) setting the visors
*) operating the time travelling chair
*) the bell ringing machine: you must make the connection that it is the order
   of the poem that's important, and not its content
*) door lock to the earth wing of Agrippa

None are very difficult.

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Comments:
I didn't like the confusion between past and present in the cut-scenes. It was
worst in the conservatory: was the performance an echo of the past, or the
present? More generally, the whole concept of "touch an object to reveal the
past" is lame.