If you are running 64bit Linux, you need to install all the mentioned libc6:i386, libsdl2:i386 and dependencies; then also make sure to install libgl1:i386, libgl1-mesa-dri:i386 libtxc-dxtn0:i386, if you use opensource graphics driver - all intel, AMD if using radeon driver, Nvidia if using nouveau driver.

After that, rename or delete libstdc++.so* in /lib subdirectory inside directory where you installed crimsonland.

No, two things:
- library overloading will cause to prefer all library versions, not just few, which can cause issues if oss,glibc or older xlib are used.
- "Instead of deleting" - no, they can be renamed or removed or moved away, this is done in 2 seconds.
Overloading the library requires to edit the .desktop file (~/.local/share/applications/gog_com-Crimson_1.desktop), or type the same long string over and over.