The good thing is that this current problem does not affect the direct downloads (for example from IndieDB or my website), only the Desura version. The bad thing is that the game won't even start in many popular Linux distributions when run from Desura! My mistake was that although I tested the stand-alone versions in several different distributions, I tested the Desura version only in Ubuntu assuming it would work everywhere, because the game files are identical.
I have spent this week tracking down the problem and trying to figure out a workaround to it. The root cause is Desura installing a libXaw.so.7 library version that is incompatible with many Linux distributions. For more technical details, see forum post here: Indiedb.com
The "bad" dependency has now been temporarily disabled, so it won't be installed with the game anymore. This resolves the problem for Linux distributions that provide the library by default (e.g. Debian and many distributions based on it). If you are facing this problem and have the game already installed, you need to uninstall and re-install it.
However, now that the library is no longer automatically installed, the game will silently fail if the library is not available (e.g. Fedora). In this case a libXaw package needs to be manually installed using distribution's package manager.
To help with similar problems in future, I have implemented an error dialog that is shown when some library loading fails instead of just printing that information to console, which is not visible to user launching the game from Desura. This will be available in next release.