Slightly better than SELF MADE MAIDS.
What, you want me to say more than that? OK. THE PLAYHOUSE is pure genius. The first seven minutes or so is the sequence where Keaton plays every part, and as Paul correctly points out, parodies Thomas Ince with the programming as far as taking credit for everything. The amount of roles Keaton plays here is breath taking, and the amazing thing is he doesn't half ass any of them. Even when he's playing the instruments, I can at least vouche for the stringed instruments, being a bass player, that he is at least attempting to portray a believable left hand fretting technique, even doing upward slides and vibrato. I say this as being impressed to his attention to detail. The roles he plays, be it an old lady, old man, child, black faced minstrel, dancer, monkey, whatever, is all played with conviction and convincingly. Every single one of them, and it's damn impressive. As already mentioned, Elgin Lessley deserves praise for the camera technique, especially getting nine Keaton's on screen! He had to use masking tape on the lens in perfect ninths (!) and make sure he cranked the camera at the same tempo all nine times to make sure everything fit on the screen properly and was running at the same tempo. Incredibly difficult to do, and the results are worth it, as it's a wonderful effect.
The rest of the film is good fun, if not as virtuosic. The running gag of Keaton getting the twin girls confused is great stuff, as is the whole Minstrel show setting in general. Again, another time capsule of a form of entertainment no longer existing in this day and age. The Zouave stuff is fun, love the Siamese twin soldiers and just this whole short in general. An unquestionable classic.
Here's footage from a 1929 short inspired by THE PLAYHOUSE from Lupino Lane called ONLY ME. Haven't seen this in about ten years.https://m.youtube.com/watch?v=t1cxamgQ6GI