Works fine for me on a fresh Debian 11 amd64 install, substituting the libmysqlclient-dev:i386 with libmariadb-dev-compat:i386.
Literally all commands until cod2 server got started:
Code:sudo dpkg --add-architecture i386 sudo apt update sudo apt -y install libstdc++5:i386 sudo apt -y install gcc-multilib sudo apt -y install libmariadb-dev-compat:i386 sudo apt -y install g++-multilib sudo apt -y install git git clone https://github.com/voron00/libcod cd libcod ./doit.sh cod2_1_3 cd .. nano run.sh chmod 700 run.sh cd cod chmod 700 cod2_lnxded_1_3 cd .. ./run.sh