Game looks neat and all, but honestly, when the game is around 200 MB compressed and over 4gb uncompressed, that suggests quite strongly that the way it handles data is very poorly optimized. Literally the only other game I've seen that compressed that severely when zipped (down to less than 5% original file size) did so because it contained Literally thousands of near identical data structures each of which was full of hundreds of identical entries with the only difference being that in some of those entries (1-5 out of the several hundred) there was a 1 instead of a 0. It took them huge amounts of space to say something that could have been simplified as, basically, Structure #X, Entry A, D and Z = 1, the rest = 0. And probably further simplified beyond that.
I don't know why exactly this game's data density is so poor, and I suppose it's not a huge problem for most people, but in the future you might want to look for a way to make sure your duplicate data is only present once with the differences being marked, rather than repeating identical data over and over and over again.