I went into the game understanding there were multiple endings, which didn't bother me. One spoiler I had unfortunately heard long before playing was the "Would you kindly?" mind control, but it was still neat to see it fall into place.
Speaking of Ryan, he and Atlas/Fontaine were great to follow through-out. The antagonist-twist reminded me a bit of Portal 2.
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http://img812.imageshack.us/img812/3492/eponaharr.jpg
Nominate SuperNiceDog's Guru-choice, then Epona.