I enjoyed the episode. I'm not going to lie, when I first saw Jason Alexander appear on screen, he looked a lot like Dan Harmon.
I like that they're continuing to strech boundaries, even if 30 Rock already did a puppet episode. It was still good. And the songs were done well. I saw on Twitter that Adam Levine helped write one.
The only thing that throws me off every time it's not live action is that the jokes don't always have the right inflection and don't always land. It happened in the stop motion ep, and the animated one from earlier this year. Troy and Abed especially seem stilted and unnatural when you only hear their voice coming out of a different medium.
Also, Annie admitted to academic fraud and Troy to a felony in front of the Dean. That seemed a little weird to me.
I did like the line about "Professor Duncan hasn't been around in a really long time."
And once again, they found a way to isolate Chevy Chase so the whole cast wouldn't have to deal with him.