That glass cage
I think that glass cage is the most "Kaufmanesque" moment, or scene, or object, of the whole movie. It's absolutely ridiculous and over the top, and yet all characters seem oblivious to it. Training to behave at the opera with all props and clothes on was so hilarious on different levels, and so to the point (we are conditioned to these silly behaviors so we can 'get some'), it is THE CK moment of the film.
The script did seem to need a bit more polish though, specially at the first act, and had a musical number that didn't work so great. It's very similar to the early unproduced material from CK, it has that spirit of insanity into it but it's not quite there yet.
"You keep him in here, and make sure HE dosen't leave!"