I'm reviewing the whole first episode here (which includes "De-Zanitized" "The Monkey Song" and "Nighty Night Toon") so...spoilers for a plotless, continuity-defying cartoon, I suppose?
Man, talk about a show that had its voice down near-perfectly from the jump. "De-Zanitized" is such a perfectly-crafted segment, with great classic Looney Tunes-style humor on display, much in the vein of Bugs Bunny, of a trio of wacky goofballs vexing and easily-perturbed straight man. There's such a out there wryness to everything that really sells it.
The other two segments are a bit fluffier. "The Monkey Song" is surprisingly catchy, and has nice moments for everyone. The same goes for "Nighty Night Toon," which, while riffing on the classic children's book, is mostly a fly-by way of giving each of the secondary characters on the show a little of the spotlight. But overall, I was really impressed at how much this show felt like Animaniacs from its very first segment.