Achron; "We're very strongly considering it! However, we've had some issues getting a single binary to work on both Debian Stable and the latest build of Ubuntu at the same time." (via email)
AirBuccaneers; "For Linux version there is more work that we have not done yet."
Anomaly: Warzone Earth; "Yup, we're gonna do that, but not sure how much time we'll need for the integration." (via email)
Bastion; "No guarantees or estimates at this point"
Beep; "Yes, I do plan to release BEEP for Steam Linux. Probably sometime in the spring though as I'm currently very busy" (via email)
The Binding of Isaac; "late January"
Blocks That Matter; "We are currently talking with Valve to get access to the beta Steam Client. We were busy and missed the beta launch
But I think on Monday we will have access to the client and the libraries!" (via email)
Dungeon Defenders; "We're gonna talk to Valve about it so no guarantee/details/etc about it happening or not, right now."
Droid Assault; See Revenge of the Titans
Euro Truck Simulator 2
Hacker Evolution: Untold; "We are working on it right now. It will be out as soon as possible and not later than the end of this month." (via email)
Offspring Fling!; "I would say its about 50/50 right now...I need to change how the final application is built. I basically need to wrap Offspring Fling with software to make it into a Linux executable, but currently I'm having some problems getting it to work for unknown reasons... until I can work out these bugs, I can't get the Linux version onto Steam." (via email)
Revenge of the Titans; "Yes, when we've got a bit of time"
Shadowgrounds; " We will probably bring the other games to Steam Linux at some point, at least Trine... but I can't promise it just yet so no ETA, there's some other issues involved (we didn't port them ourselves and they have a bit too many technical issues compared to Trine 2). But it will most likely happen at some point.", "the SG games are a bit 50/50, we sell them elsewhere but they bring a lot of support issues in their current state so we're hesitant to broaden the audience too much if we can't get the issues fixed... But we'll see how that goes." (via email)
Shadowgrounds Survivor; See Shadowgrounds
Shatter; "Eventually - our guys are pretty tied up just at the moment, but that's the plan."
Titan Attacks!; See Revenge of the Titans
Toki Tori; "About Toki Tori 1 Linux, yes we are definitely going to bring that towards Steam Linux, but we are still not sure when" (via email)
Trine; See Shadowgrounds entry & "I think Trine is a given, just needs some time (i.e. spring)" (via email)
Vessel; "We will! Gonna fix some multithreading issues first so its fast though." (via email)
PROBABLY NOT COMING: The following games are unfortunately not coming to Steam or are unlikely to come to Steam, even though they have Linux versions.
Avadon: The Black Fortress; "It might happen someday, but it would require a bit of work on our end and we-'re swamped with Avadon 2" (via email)
Botanicula; "well, we do think about it but right now we are too busy. I am sorry." (via email)
Machinarium; See Botanicula
Samorost 2; See Botanicula
Spirits; See this
Super Meat Boy; See this
Wizorb; "we have no plan to release Wizorb on Steam" (via email)