You can go east or west from the entrance.  There isn't much point in
doing so, however.

Dust is mentioned if you take the key out of the skull, then close and
open it again.

The troll yells "You can't trick me" when you try to attack him with
something other than the spear.  This is in the original game.  Perhaps
I should change it to something that makes more sense.

You can also use a gem in the sling.

The Biblical reference when using the sling on the cyclops is from the
original game.

All those instant death things are also from the original game.

Other objects may be tied to the rope and lowered down the well once
you've taken the bucket off the rope. There's no particular use for this
other than a curiosity.

Yes, you have to do the sphinx riddle every time.

You need to examine the marks scratched on the stairs in the Sphinx
Room.  The lever room solution is one of those puzzles that was
randomized.

You can safely discard burned-out torches.