I am trying to run X3:Reunions (Linux version) on Kubuntu with help from minigalaxy and I am getting the following error:

./X3R_config: lib/libz.so.1: version `ZLIB_1.2.9' not found (required by /lib/i386-linux-gnu/libpng16.so.16)

Judging by the lack of a slash before lib in the error message it's a lib directory inside the game directory. If it's really the case then go there and rename libz.so.1 to something like libz.so.1.bak or just move it out of that directory and try to launch again. If you'll get missing library error - try this: sudo apt install zlib1g zlib1g:i386 (AFAIR X3 is a32 bit game)

This solution fixed X3: Terran War Pack for me some time ago on Ubuntu:
https://www.gog.com/forum/x_series/x3_terran_war_linux_shared_library_issues/post5

THANK YOU FOR YOUR ASSISTANCE: I will upload a screenshot of /home/user/Storage/Gog Games/X3 Reunion/lib/
until I got your response I thought the libz.so.1 was suppose to be in this location: /lib/ (still trying to understand how packages work).

I right clicked on the white background of that window (in the picture) and went to "actions" then "open terminal here" and at this prompt:

user@computer:~/Storage/Gog Games/X3 Reunion/lib$ sudo apt install zlib1g zlib1g:i386

I TYPED IN PASSWORD THEN I GOT THE FOLLOWING:

Reading package lists... Done
Building dependency tree
Reading state information... Done
zlib1g is already the newest version (1:1.2.11.dfsg-2ubuntu1.2).
zlib1g set to manually installed.
zlib1g:i386 is already the newest version (1:1.2.11.dfsg-2ubuntu1.2).
zlib1g:i386 set to manually installed.
The following packages were automatically installed and are no longer required:
kfind libkf5konq-data libkf5konq6
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Tried to run X3 in minigalaxy and also by right clicking on the start.sh file and selected "Run in Konsole"

GOT THE FOLLOWING RESULTS:

./X3R_config: lib/libz.so.1: version `ZLIB_1.2.9' not found (required by /lib/i386-linux-gnu/libpng16.so.16) THANK YOU FOR YOUR ASSISTANCE. One of my problems is I don't seem to even have: libz.so.1 anywhere.

One of the main reasons I am doing this is to learn how to troubleshoot these kinds of issues better.