Andy's Gang, so to speak, never actually existed. The audience of children was stock footage. The cheers and laughter all canned. Andy filmed the whole series in an empty studio. Just to add extra weirdness, to this already creepy show.
The clip featured on Weird Retro and shared across facebook, was the infamously creepy rendition of Jesus Loves Me by Andy, 'accompanied' by Midnight on piano. There is an urban legend that has grown-up around the clip, that Squeaky The Mouse (hamster) actually died during the filming. (It is supposed to happen around 1:05 into the clip.)