RetroMessenger requires a few SDL2 libraries to run.

Install dependencies:

    sudo apt update
    sudo apt install libsdl2-2.0-0 libsdl2-mixer-2.0-0 libsdl2-ttf-2.0-0 libsdl2-image-2.0-0

Then run RetroMessenger:

    ./RetroMessenger

If you see a permission error:

    chmod +x RetroMessenger
    ./RetroMessenger