Full credit goes to this guy:
http://steamcommunity.com/discussions/forum/1/492378806384752367/

Which is how I found out about it. It's in the format of a Steam key, but still, free game. You can grab it for free up to the 29th of November.

We actually know: http://www.gog.com/forum/general/free_temporary_keys_giveaway_central_topic/post1420

But cheers!

It does work! The only cost will be extra spam E-mails from Square Enix...

Thank you!

Oops, sorry about that. I did a search for Silent Assassin, but I was skimming the titles of the discussions and didn't think it might have been mentioned in an existing topic. I'll be more careful in future, and thank you for the heads up.

S'okay - seems a few regulars aware of the topic missed it first time around at any rate.

I've a question. If you get Silent Assassin from the NA store, you get a Steam key? And if you get it from the EU store, you get a DRM-free download? Because that's what I noticed.

yup thats sounds right, my EU buddied got dl and i got steam key here in NA

Thanks for the heads-up! Got it. :)

I got a Steam key despite being in the EU and using the EU store (from Germany).

Thank you for the info, i just got it. By the way, yesterday i try to get it, but apears to me a message saing that the were no more keys. So if anyone get the same message, just keep trying. +1.

Well, it seems i was late & the site says unable to process order as there is no more stock. If any1 manages to get an extra copy i wld appreciate if i cld get it, thks. :)

Update: It seems that the keys do indeed replenish aft some time so i also suggest those who missed it earlier like i did give it another try. I can't be sure how many more keys r left & if so when they wld be replenish again. Neither do i know just how long more this promo is up but i dun think it wld be ard for long. Gd luck ppl!