Thanks flipalong but that didn't solve it, as it was the first thing I tried

However, I didn't know how to see the installed packages (not apps) and you have shown that to me. Because of that I realized I have installed libgles2-sgx-img, what is an upgraded version of the same library, but gltron depends on the previous one. I still don't know how to check which packages do depend on a single package. If I could do that (with 'dpkg' I suppose, but I haven't found the specific parameter for this purpose) I could check wether I can solve it by uninstalling the apps depending on that package (in case I don't care uninstalling them) or that library (the upgraded one) is a dependency for more important features, like CSSU or so.

I have no idea on porting or such, to build gltron again, but against this new library. I'm not even sure that this can be done.

I'll keep searching, but any help would be appreciated.

EDIT:
"Pheeewwww"... Many apps depend on that. I can't uninstall the package and install the previous version.
I'm stuck here...