The storyline is pretty mediocre but the actual gameplay is solid. I got it through Gamefly and didn't regret it, but once I'd beaten it I had an opportunity to keep it for 13 bucks and didn't bother.
I don't know if it has a demo, if it does try the first puzzle and use that to decide if you'd be interested in playing a more complicated version.
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SuperNiceDog buried everyone else's hopes of winning the Guru contest in the backyard.