Also, some games that work fine (like Osmos) aren't listed there.
Users have been using http://www.reddit.com/r/linux_gaming/comments/15502w/the_big_updated_list_of_which_steam_for_linux/ as an unofficial list, which reinforces the confusion in having games listed yet not downloadable (DEFCON), not listed & not downloadable yet visible in client (vvvvvv), and games downloadable that arent officially listed (Tiny and Big, apparently, but I haven’t tried that).
There have been some recent changes and the article now reflects this accurately.
To see the up-to-the-second list of supported games, click the Linux tab on the Store page of the client. Any other method is not guaranteed to be correct.
@frankc-valve The Linux tab results are not correct either. DEFCON is listed under the store's Linux tab but it doesn't download and install the game data and therefore the game cannot be played under Linux.
Nothing extracted yet.
The list of games located at https://support.steampowered.com/kb_article.php?ref=8495-OKZC-0159 is inaccurate.
Of the games listed, the following games have been reported on this tracker as not working (at time of writing):
DEFCON
Multiwinia
(Part of) Penumbra Black Plague Gold Edition
Waking Mars
Could we possibly update the site to have accurate availability?