Of the 12 individual stories in this trade, I liked five of them. Dorkin's classic Elseworlds story from which the book takes its name shows him at his anarchic best, deconstructing the DC universe alongside many of the most iconic artists in the publisher's history. It's great and deserves all the praise written about it from me & everyone else.
That one story aside, I think I have a clear preference for the stories showcasing Bat-Mite over Mxy. I appreciate the World's Funnest TPB for showing that Bat-Mite functions best in spaces & stories that engage in commentary re: tropes pushed on the comic reading public. It should come as no surprise, considering his origin and first appearance, that the stories here offering the best metacomentary are the aforementioned title story, Alan Grant & Kevin O' Neill's send up of the truly ridiculous Knightfall saga, "Mitefall", and "Li'l Leaguers" by Green, Johnson/ Albuquerque. I think I was most surprised by "Lil Leaguers", because 1). How can any reader not be impressed by combos like Grant/ O'Neill and the once-in-a-lifetime collabs by the likes of Dorkin/ Gibbons, Dorkin/ X. Hernandez, Dorkin/ Allred, Dorkin/ MILLER yeah that's FRANK Miller, making light of himself for once, et al, and 2). I was caught off guard by the way Green, Johnson & Albuquerque take aim at that era of singular writer-artists depicting familiar heroes as young children in a vibrant comedic tone (think Art Baltazar's Tiny Titans, who make a cameo appearance here). That moment owes a great deal to Bat-Mite as a character, and I had never been able to connect those particular dots from the Silver Age to the Modern until they were laid out here.
The other Grant/ O'Neill story is fun, packed with satiric detail in every panel, but not as strong as the later "Mitefall", and I was particularly taken by the effectiveness of Siegel/ Shuster's original Mr. Mxyzlptlk story. There's my five.
The rest of the stories in the trade suffer from unfortunate comparisons to either Mxy's first appearance, or Bat-Mite and Mxyzlptlk's finest hour in the first story of the whole book. Or, in the case of Bat-Mite's first appearance in Detective #267, the plot just isn't as imaginative as the character of Bat-Mite himself. So yeah, to recap: WORLD'S FUNNEST is a 5/ 12, or 2.4 stars for those exclusively interested in the convoluted conversion of all analysis into easily digested rankings by "stars".