You don't actually need the rock to win! You just have to make Whirlin turn into a rock (by turning into a Dragon or a Demon when he's a Dragon), so don't give up just yet! And thank you, I really appreciate the compliments!!
I'm also running into the "lose the duel because the menu takes too long" problem. Any chance that either the duel could become not timed, or a faster interface for forms that lets you see all of them at once could be implemented?
I could add an updated version with a longer timer, which would probably help somewhat. I'll also look into the faster forms interface too, since its' a complaint I've been seeing a lot, but I can't promise much on that front.
UPDATE: I've added a new version of the game with some fixes that should hopefully help fix your problems!