after unzipping it, you should have a "potion" folder containing a "res" folder and two executables.. run one of those (potion_w for windowed mode, potion_fs for fullscreen) in the same way you usually run stuff - double click from a GUI file manager window, or type ". /potion_w" etc from commandline.. or is it that you're doing that and it's not working? i now have he sneaking suspicion i've forgotten to do something it needs for max compatibility.. will check later..
trying to run potion_fs or potion_w gives error:"there is no application installed for "shared library" files. Do you want to search for an application to open this file?" , clicking yes redirects to an error message in the software center (where to install stuff via gui). the software center then says " Unfortunately, the application/x-sharedlib file format you were searching for could not be found. Please check out <a href="https://help.ubuntu.com/community/Repositories/">this website</a> for more information.
What did you forget to include? sounds like a panacea to compatibility issues :D
aha! looks like the problem is because (at least some flavours of?) linux don't like running executables directly from a GUI/file explorer window - you're meant to have a special .desktop metadata file, or a shell script.. i've updated it (grab POTION_linux_v2b.zip) with some shell scripts in there ("run_windowed", "run_fullscreen") which simply load the executable - hopefully these will make it work! seems to do the trick here. sorry about that, i just run things from commandline so didn't notice this was a thing.. please let me know if you try it and still no luck.
(the thing i thought i might've forgotten was to link it to the included copy of the GLEW lib - had this problem in the past, not all linux distros have this lib in their repos apparently. but nah, i'd remembered it this time, phew)