>>234796 Fleischer studios to be exact. It wasn't a simple matter of parodying the nebulous concept either. They where very spesific in how they made the parody. The designs, the plot, the progression, the animation, the gags, the voice, the tone, even to the point of adding the superman reference with a design that reflected the original.
They where very particular about the episode and it's very clear the animators have a great deal of respect for early animation, and the concept of nostalgia as a whole.