The Let's Play PiD I've read and you link to seems to indicate that you can get another gemstone, it does fit in the box, and it is worth over $100k (but no more points). I am eager to see if this is true.
And Watch Your Step is a fiendishly constructed plug on the no-damage dreams. The only Pale Violet potions are under it. I would even have gone so far as to beat the game, go back from I'd Rather Be Surfing to get the bomb and then eat the easter egg again to plant it (presumably having been lost the no-damage caveat later)...but again, you can't do that without the Green Crystal. It might be possible to speedwalk over there from the ladder and grab it with a Bubbling Red Potion...but I'm out of those. I could revert to an earlier save on Lasciate and give it a go, but then I lose an hour's work going after the Crystal and will really need it for the ghasts and phantasms yet to come. Decisions, decisions.
: Cool. Hope you don't pay for it at the end. You might need that potion. I am
: certainly interested to know what happens after you finish the last level
: and then eat the Easter Egg. In particular, whether you can actually pick
: up two Alien Gemstones. Did Jason code something in for this eventuality.
: Might be a hidden surprise.