Chocolate Doom is a Doom source port that accurately reproduces the
experience of Doom as it was played in the 1990s

To play the game, you will need at least one of:

doom2.wad from Doom II
doom.wad from Registered Doom or Ultimate Doom
tnt.wad or plutonia.wad from Final Doom
doom1.wad from Shareware Doom (available on SBo as doom_shareware_data)

Place the WAD file(s) in /usr/share/games/doom.