• Because time is fluid -- and so is this game. It's really never the same game twice (something reviewers didn't mention). While who has the crystals doesn't change, where they are does. And who you meet changes. And whether or not they try to kill you changes.

Things that don't change:

• Don't trade with the Neanderthals until you've traded with the Partian. (Don't worry: they'll wait.)
• Get into the laboratory and drink the medicine in the vial as soon as possible. And grab that bag!
• Go for the clear crystal last.