https://vimeo.com/127459737

It has a weird almost flood of dark blue at the end of the clip in the top right corner? is this from the incorrect gradient filter?

That's most likely banding (compression artefacts). You have too much movement in the foreground, this eats up the bandwith, so the encoder treats the sky as a flat blue surface and compresses too much.
Make sure to use longer exposure times next time (nd filter) to blur the movement of the people this will help with overall quality and give much better visual appearance.

I thought about that, I was honestly worried about using an nd for night time stuff. I have an ND 3.0 but that is definitely too much, u think an nd .6 would do the trick?

It depends of the darkness that you are shooting in. Just try what exposure times you can get with different ND filters. In city conditions, normally it doesn't get really dark.