It was a good episode, though I have to say it was a step backwards from last week's. First, what I didn't like. I, too, was anticipating this one to be more of a Mac and Frankie-centered episode (according to the description from Cartoon Network's website), and it wasn't quite there. That took a bit of enjoyment out of the episode. Also, I wish Frankie and Herriman would've put up more of a fight vs. Lincoln and Moose. Really, that's about it, though it was enough for me to lower my grade of the episode.
What did I like? I loved the first act quite a bit. I enjoyed Bloo's Daffy Duck-esque act in Mac's classroom, and Bloo's obsession with the video game. I really loved the musical bit in this one. It was great to hear some of the IFs use their vocal talent there. I hope to see another in the future.

I loved Herriman's first lady line there.

I must that that Lincoln's design is unique and I wasn't expecting him to be so small. I also loved how Madame Foster used Lincoln at the final act of the episode.
Overall, this isn't a favorite episode, and I had hoped it would've been better. I have to give it a B-. One more Season Four episode left, and we have the movie coming up in a few weeks.