A small correction. You are linking us the app, not the sub. Amazon is selling keys, so it should be sub 15204. You'll notice the "billingtype: Proof of Prepurchase Only", aka key, as well as the list of countries that cannot purchase this serial.
As for what can and can't be redeemed, my XCOM:EU is the russian version, and I did play it without needing a VPN after the first 12 hours or so. It is currently impossible to redeem the game though, since the sub has changed. But the app id is still the same.

And yes, I did forget a few more regions, including Germany, Australia, Japan and China, and quite probably a few more.

Additional info. Only region locked "Front Mission Evolved" retail key is the Japanese one. Would a screenshot of me having redeemed a Russian FMT say anything about the rest of the RU keys? So it remains a game by game case for whether NA keys are region locked or not, no matter what our previous experiences with them were :(

Looking for The First Templar steam game from new bundle stars.

*Updated

Just looking for these if someone has the extra keys

Lucius key
Proteus key
Hotline Miami key
Serious Sam 2 key

Just to make it even more obvious.. the only keys GamersGate sells for Front Mission Evolved are EU, so if they were region locked, I'd be screwed since I live in NA.

So yeah.. the only region locked keys for that game are Japanese, otherwise I wouldn't have been able to play it lol.

traded! YAY ;-)

could you provide me with a link for it just checking something ;)

http://store.steampowered.com/app/222160/

thx not one I have access to unfortunately

Np ;-)

It was in the IR Winter bundle and now it's in the current BiaB. It may have been in others - not sure about that though.

Got it in a trade ;-)

BiaB?

Bundle in a Box

thx one I haven't bookmarked yet ;)
Dang not one game I would like in that sorry MOMO

Like I said - a SPARE, please! It will go on sale or show up again in a bundle ;-)

If anyone happens to get a Serious Sam 2 key they don't want, I would appreciate it. Thanks!

EDIT: Nvm, Bigs gifted me the game once again. Give him some rep. Thank you very much Bigs!! :)

Is not a priority, so consider the requests of the other people before, but if someone has a Serious Sam 3 BFE spare key, would be appreciated! Thanks!