The game is under 5GB, if you can't get it on mega, it's because you downloaded something else first. You can use a download manager or VPN to get it from mega or you can download it from gofile, the links are on patreon/SS.
There are no costs at all. The game is free and you're free to decide whether you want to donate or not.
The next version, V0.15, will be over 5GB, that's what I meant by tough it out. For V0.16, I'll be switching to a new version of the game so it'll be about 250MB.