While the animation from the old shorts was reused, the backgrounds in those clips were re-designed. It is most evident in the clip from Robin Hood Daffy (1958): The sky in the original short was yellow, while it's blue in Mucho Locos.
The film marked the final appearance of Porky Pig in the theatrical shorts of Warner Bros. Cartoons. The character only makes a cameo appearance.
A darker premise of the imagination shown here appeared in the film "Jakob the Liar" many years later.
The curious looking space age items perched on the house roofs are state of the art (for the time) television antennas!