One comment about this Quest: there are (at least!) three solutions to the Secret Switch; Easy, Trying and difficult. My "PERFECT!" was done the 'Easy' way (IMHO). It may be faster in either of the other choices.
Followed Swietymiki's suggestions to prevent completion without solving either Secret, fixed some minor graphics errors, and did a GAMMA test, proving that the 'trying' solution to the Secret Switch is indeed possible (a bit slower).
It is now directly downloadable if you can't wait for the distribution email.