I have a weapon in a game in very early development which is like a light saber from star wars including the audio which sounds different but similar and I'm wondering if anyone knows if there would be any copyright problems. I have a video here

As long as you don't call it a lightsaber and stick to the free license sounds, you should be fine.

Their have been enough "not quite" lightsabers around that I think you're fine as long as you don't directly copy the effect or the sound.

In the video clip I see a purple knife around a ship.

Isaac Asimov used energy blades in the 1950s, decades before Star Wars had a light saber. The concept of an energy blade is generic and is common in science fiction. Several specific names (e.g. 'lightsaber') are covered by trademark. Distinctive audio and imagery is covered by copyright. Don't use those names, audio, or imagery.

Make an energy blade that is different from those found in other products and you're fine.