See @AbstractPanda for my reviews of experimental films.
Yeah, this doesn't even really deserve mention for the historicity of sync sound. It was obviously dubbed in post, they only bothered foleying like 1/4 of the actions, and most of the sounds present were just whistles or distant barking. It's more like…first cartoon with sounds added in post, and replayed at approximately the same time? So yeah, it's honestly fine that Disney "snuck" theirs into release ahead of this. The music was pretty decent.
The cartoon itself was actually…