You can clone with
HTTPS or Subversion.
It's great that the game code is open source.
Are the art assets also freely licensed? In that case it'd be useful to state that in the readme. If it's not yet but you're interested, I recommend http://creativecommons.org/licenses/by-sa/3.0/ .
If you want to make the graphics remix-able, it'd be great to have the 3d models in a gfx_source/ dir or something like that and if the "source" of the music is small enough for online sharing (and you want to to be easily modifiable), it'd be interesting to have that too.
Thanks for the question! I was expecting somebody would bring this up eventually, but I wasn't expecting it to be so soon :D
I made all of the art assets, and was considering CC BY-SA for them. Some of the audio assets are derivatives of stuff on freesound.org, and I'm not 100% that I've identified all of them, so I've been holding off on adding licence until I sort that out.
I hadn't really put much thought into getting my .blends out, but that's definitely a possibility too.
If this is stuff you're personally keen to see, I'm happy to do some extra legwork to get this stuff sorted sooner. If not, it might take me a month or two to get around to.
You could put the .blend files on opengameart or blendswap if you feel that your repo isn't the right place to share them.
In your Freesound profile you can see a list of sounds you downloaded. That might find figure out which you used.
What about the creation of the music? (I really like the two action tracks! They also reminded me of Wolfire's 7DFPS game's music.)
Personally, I'm not in a hurry. If the music has "share-able" sources I'd be thrilled to see those. :)
All of the sounds that I worked on I recorded personally (the pain sounds and some of the skating sounds). I've asked the other guys if they can help me track down what they used. Hopefully we'll sort it out soon :)
It's funny that you should make mention of the music that Wolfire used for Receiver - Anton Riehl composed both (it was awesome to collaborate with him on FLAT). I'll ask him about licences/sources over the next couple of days.