I don't know if this is a common/standard thing for you to do, but I noticed you used a piece size of 1MiB for a torrent that was over 4000MiB in size (resulting in equally as many pieces).
Any reason you're not following the ~1000 piece guideline? Even uTorrent <3.0 (which no one should be using at this point) supports up to 16MiB pieces.
Having too many pieces in a torrent can slow transfers down noticeably if it gets high enough, and bloats ram usage by the client. There may also be an impact on the disk head when it comes to seeding (though unlike the other two problems, I can't personally confirm this).
There are math equations that can be used to create a .torrent with its ideal piece size such as:
Code:
piece_size_in_bytes = 2 ** (int(math.log(size_of_data_in_bytes) / math.log(2)) - 9)
Could easily be capped at a max size as well, for example for 64MiB:
Code:
piece_size_in_bytes = 2 ** min((int(math.log(size_of_data_in_bytes) / math.log(2)) - 9), 26)
PS. While I understand your reasoning for serving zips, it's a damn shame for people that might want to seed, since they'd have to store the game twice to do so.