Thanks for the feedback, and sorry for the Josh Roberts-esque delay in response!
Firstly, an updated version is here:
www.zombie-cow.com/btdt
with keyboard shortcuts and a few other small enhancements/fixes. We never really bothered with it because we personally don't use them, but as the game grew popular and this point was raised surprisingly regularly, Dan coded it in.
Re. the yin/yang dark/light: they're from alternate dimensions, where it's the other way round. (Sci-fi is great for explaining away mistakes!)
I suppose the castle could feel like a loose end. It's basically there for exposition, but I like the dialogue with the king, and I don't think it's necessarily bad design for things being there just for fun or cementing the game universe, like say the guests at the yeti party in Sam And Max Hit The Road.
Cecil is the T-Rex. He may never get to work, but he certainly learns his lesson for being a lazy games programmer!
