No joke when the game comes down in just one zip file that weigh's in at a huge 15.4GB. So if you still have a slow connection and/or mean bandwith limits then you might want to reconsider taking the risk.
I don't think it does come down as one big zip file. From what I have read, it comes down in smaller chunks, and once it has downloaded all the chunks, it combines them into a zip file. The problem lies in the fact that it does not verify the chunks are correct before combining them.
If they were to just implement the verify files like Steam does, it would be fine.
Exactly same problem when trying to install last night
I too had this problem. The first time I downloaded it with corruption, I opened the zip in Winrar, and it told me which file was corrupt. I then deleted the 16GB and re-downloaded it, and this was corrupt, but a different file this time.
Having already downloaded 35GB of files, I didn't want to do it again, so used Winrar to extract the files (skipping the bad file), then re-zipped it without the file.
Capsule was then able to install the game, and so far the game runs OK. If it crashes later, I may then try downloading again.
Steam is still better, but Capsule is not too bad.
& no it does not register on Steam either you have to use GMG Capsule download manager.
superb game.