I bought the Humble Indie Bundle 13 and downloaded Risk of Rain (non-Steam version). Tried firing it up, when it wouldn't run, giving error:
"error while loading shared libraries: libopenal.so.1"
Found that it required a bunch of 32-bit packages, namely:
which you had to install with "sudo apt-get install [package name]"
NOTE: To get "Shadowrun Returns" working, also had to install the "libxcursor1:i386" package.
NOTE2: Am running Ubuntu 14.04LTS 64-bit