When it comes to music/ soundtracks it can affect the audience and cause the audience to interoperate the film differently. Un Chien Andalou by be a silent film due to its time period but it did have music. A gramophone was played to go long with the film.
The film was restored but had changes done for example the original was 16 and the restored version was 21 minutes long. This is because the restored version was slowed down to be in real time compared to the original which was sped up in places. The restored version also had different a score/ soundtrack, like a said above affect how the audience receives it. But the soundtrack for the restored version un intentionally give the film some meaning.
80 years since the film was released and yet most people have seen some of film. Most people won't know the film. But its due to a scene in which a woman has her eye cut open with a razor blade, which was done by editing the footage of the woman and a dead pig getting its eye cut. A very shocking scene which keeps people talking about it, true nowadays we are exposed to a lot more but this was the first to do it, plus that was still a real eye.
By watching you can tell its Dali's work, as the film has a scene that has the iconic image of Dali with his had covered in ants. Dali used ants in his work to symbolise decay and decomposition.
This image below is part of dali's most recognised piece of work called "The Persistence of Memory" but most will know what your talking about if you say melting clock painting.