Very nice.
It kinda feels like it ends before it gets past the stuff I could guess from knowing my way around other scripting languages, but I'm guessing it's a work-in-progress. It'd probably benefit from even a brief "Why Lua?" discussion, though.
It's very pretty, but I'd consider getting rid of the text-shadow on code examples.
(Minor point, but: # as a length operator isn't entirely unique to Lua, Perl has $#foo to return the length [kinda] of the array @foo).