Went to install the game on my steam deck.
I installed it through the terminal by executing the shell script installer.
At the end it failed and wrote a "broken pipe" message over and over again.

By looking at the process name I saw it was the postinst.sh script.
This script takes files that were split and concatenates them back together.
While it concatenates the files it tries to launch a gui window with a message "Please wait".
The thing that fails is launching the gui message, so manually concatenating the files works around the issue.

Here is the workaround:

Kill the postinst.sh process (it gets stuck in an error message printing loop).
Go to the install directory
Run:
cat game/Ruiner/Content/Paks/Ruiner-LinuxNoEditor.pak.split0* > game/Ruiner/Content/Paks/Ruiner-LinuxNoEditor.pak
rm game/Ruiner/Content/Paks/Ruiner-LinuxNoEditor.pak.split0*

Now the installation is complete.

The gui window fails to lunch because it tries to load libgtk-x11-2.0.so.0 and libgdk-x11-2.0.so.0 which are pretty old.