I too have two hard drives, mainly for other games and....well, such games.Ren'Py doesn't have anything to do with your downloads. It's a programming language for the games. You download with something else: Mega or Nopy or whatever. Downloads of many of the games are pretty big, especially this one - it's 6-1/2G. You may need to buy a stand-alone disk drive to handle your games. I have two.
it's quite spacey still, and it isn't full, i've changed the pathway of the zip onto one of those harddrives as well, but still it tells me that it's full.
The thing is I have downloaded other games, RPGM and Unity games seems to work just fine, but Ren'py games, they don't and as aforementioned, things happen.