Crispy Doom is a limit-removing enhanced-resolution Doom source port based on Chocolate Doom.
Its name means that its internal 640x400 resolution looks "crisp" and is also a slight reference to its origin.
Crispy Doom is a friendly fork of Chocolate Doom that provides a higher display resolution, removes the static limits of the Doom engine and offers further optional visual, tactical and physical enhancements while remaining entirely config file, savegame, netplay and demo compatible with the original.
The canonical homepage for Crispy Doom is https://github.com/fabiangreffrath/crispy-doom, which also hosts the Crispy Doom source code and provides building instructions.
Official binary releases for Windows XP / Vista / 7 / 8.1 / 10 (both x86 and x64 editions) as well as a supplementary Music Pack that contains the fluidsynth library and a freely-available soundfont are also announced there.
Daily builds of Crispy Doom can be found here: http://latest.chocolate-doom.org/
Crispy Doom can play nearly all variants of Doom. If you don't own any, you may download the Shareware version of Doom, extract it and copy the DOOM1.WAD file into your Crispy Doom directory. Alternatively, you may want to play Crispy Doom with Freedoom and a MegaWAD.