If you use the GOG downloader, you'll only be able to download only 1 file at a time, but you can add more games to the queue list, so that when Witcher 1 ends downloading, Witcher 2 will begin downloading.

Not quite sure what you're asking...download the game and download the .exe? But yeah, depending on your internet speed and what speed you're downloading off gog with, your net can become slow (youtube would take a couple seconds at a time buffering, etc).

I know but it doesn't work!

What do you mean that it doesn't work? You tried clicking on Witcher 1 and 2 and they aren't both added to the queue?

Yes! Better to regret doing something than to regret not having done it.

The Witcher 2 is added to the queue but not The Witcher 1. Also If I exist out of a downloader, will all my currently downloading games need to restart when launching the downloader again?

Stupid question but did you try re-adding The Witcher to the queue? As far as I know you have to keep the GOG Downloader open (and stay logged in) until the download(s) finishes.

Yes I've tried many times but nothing happens!?

That is pretty odd, I just tried downloading The Witcher via the GOG Downloader and it works for me. You could always download it manually by turning off the GOG Downloader (just click on where it says ON, just above the My bonus content)

Close the downloader and try adding the game again.

No, one of the main points of the downloader is that you can safely cancel and continue downloads.

It has actually restarted a DL for me a couple of times after I've shut down the downloader and restarted it. I think there might be some sort of bug in there.

Was this weird question really so urgent? O_o

That's what I'm curious about. XD I wonder where he lives in Canada because I'm on the border and we are due to get crushed by a storm this morning which might kill internet, so maybe he's trying to get it done before then.