I've never played this, if I download the game do I get the extras or do I have to download different files?
I'm not sure what exactly you mean by "extras". The Halloween special is standalone, so download it and play it as if it were its own game. I would recommend first playing through all of the current content for the normal game (so the links directly under
Download on the OP). This will help you know all of the characters, so when they show up in the Halloween special, you better understand them. However, order doesn't
actually matter, so you can play the Halloween special first if you're prefer.
There's also an incest patch, if you want to use that; apply that after you've downloaded the full normal game (i.e., it doesn't go in the folder for the special). There was a Christmas special at one point as well, but I don't know where that went. Maybe it will reappear this year in seven weeks or so, but I'm not sure. There are also secrets (items like bras or vibrators) to click on during free-roam mode that will give you images in the game's gallery. Finally, there are also dreams the MC can have, which are a nice addition beyond the standard story.
If you mean something beyond the above, though, you'll need to specify.