Update: I had no problems downloading the game off the client, so it would seem everything's been hammered out.
Update No. 2 by The Tingler: In case you want more proof that reviews always boil down to someone's opinion, and that opinion usually differs from other people's, Eurogamer's review is now up, and it's not quite so glowing.
Update 3 by Kroms: Yesterday's tomorrow is today's today and anyone who bought the game from Telltale should be able to play it.
Update 4: Mojo's own review is now up, again proving update 2 true!