Try running the AppRun script from the main directory, two levels up. It usually takes care of making the libraries we need loadable.
Though libstdc++ is not included, it’s a system level library. If AppRun does not work: What Linux version are you using, precisely? Maybe our build system is not compatible with it and needs an upgrade.
Ah. Sorry. Jessie is not supported by our binary builds, they are all based on Ubuntu 16.04 which has slightly higher versions of all libraries. All our binaries are the same, you don’t have to bother with AppImage or ZeroInstall.
For the binary distributions that would work with Jessie, presumably (Flatpak and Steam, they bring their own libraries), we don’t do 32 bit builds.
Debian Stretch should work; at least, we have automated tests that ensure there are no fatal library incompatibilities like you encountered. You should upgrade anyway if you can, considering Jessie is out of security update support already. So that would be my recommendation.
The only other option would be to build from source. Here would be the docs for that: http://wiki.armagetronad.org/index.php?title=Linux_Development
