Frozenbyte has announced a Linux version of Trine is about ready for release, but right now they are looking for some beta testers to run the game for about two weeks (the beta is time-capped). Trine is a side-scrolling action platform / puzzle game that was originally released for Windows last year and then a month ago was released for Mac OS X.
Frozenbyte, the Finnish game studio behind this game, is the same developer behind the Shadowgrounds series that also had a native Linux client. Shadowgrounds and Shadowgrounds: Survivor were originally being ported to Linux by an unheard of company known as IGIOS, but then it ended up being published by Linux Game Publishing. This time around, IGIOS nor Linux Game Publishing are involved with the Trine port. Frozenbyte ended up porting a company known as Alternative Games to port this commercial title to Linux.
Ever hear of the Alternative Games company? Neither have we. Their web-site is simply a simple image dropped in with basic HTML and is nothing more. After some digging, it appears Alternative Games Oy is owned by a Tapio Honkonen out of Finland. Tapio also owns the aforementioned IGIOS porting company as well as SilverQuill. Alternative Games may very well be a new company from IGIOS. SilverQuill appears to be branched out of IGIOS and is focused upon in-house game development rather than just porting games from other studios.
A title that SilverQuill is currently working on is "Iron Sky: Operation Highjump", which will also have a native Linux client. However, don't expect this game to be released too soon. The Finnish science-fiction comedy movie, IronSky, for which this game is based, will not even be out until 2011.
Those interested in applying to be a beta tester can visit this Frozenbyte thread. [Update: it appears they now have enough beta testers.]
Frozenbyte is also at work on Trine 2, which is anticipated for release in 2011 and will likely also feature a native Linux client.