How can I open a game installer in Ubuntu 18.04

I’ve tried to download the archive and unzip the file glaclient-linux. The command file glaclient-linux returns:

glaclient-linux: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter /lib64/l, for GNU/Linux 3.2.0, BuildID[sha1]=79f804d0bc700ea0ff8e33462941eec21449ac41, stripped

It means this is a native binary executable file for x86-64 (aka amd64, 64-bit Intel), so it can be run directly on such a machine (not an old 32-bit Intel or Raspberry Pi, for example). You might have to set the executable flag which is not preserved in ZIP files. To set the flag, issue the command

chmod +x glaclient-linux

in the folder where you have extracted the file (or provide its path).