NOTE: I wrote this reply based on your post before you edited it.
I took a quick look at the install script and it does not appear to include any of the things required to install a GoldSource (HLDS) server like Counter-Strike 1.6.
Take a look at the explanation in
SteamCMD: Downloading an App for HLDS (AppID = 90). They have examples for the method recommended for automation in
SteamCMD: Automating SteamCMD.
Notice that the original script yours is based on even mentioned that there is some extra stuff needed for "cs 1.6".
This is the first I've heard of Pterodactyl (I played around with LinuxGSM once but never actually needed to run a server myself) so I don't have anything set up to be able to test it.