The non-flac sounds are only 3.9MB and if you convert all .wav to .ogg (currently some are .ogg, some .wav; source code will have to be modified to include other file names, not sure if this will cause problems for looping/fast-feedback sounds), they are only 2.5MB.
It might make sense to shorten watery.ogg, which could reduce it by 0.5-1MB further. I can do this if you think it's a good idea.
Do you plan to include the .flac files? I'm not sure what I would do.
Same question about .blend files.
I've got a feature request already: Coop mode with 2 players
A new project should be started for such major changes.