Please note this applies mostly to Debian/Ubuntu, so for other distributions, please consider using their respective utilities (packet managers, installation from source, etc.)
- Download and install libsdl-dev:
sudo apt-get install libsdl-dev - Download and install GZDOOM:
sudo apt-get install gzdoom - Also, you can download the pre-compiled DEB package here: Debian.drdteam.org
- Download and unpack the OCEAN Demo;
- Place the ocean24.pk3 file as well as your IWAD (doom2.wad, tnt.wad, plutonia.wad, freedoom.wad, freedm.wad, etc.) to the GZDoom folder: (/usr/games/gzdoom by default);
- Open the terminal and type:
gzdoom -iwad doom2 -file ocean24.pk3 - Have fun!