GlHack is a port of the game NetHack, using hardware acceleration via OpenGL(R) to render the 2D tile graphics. It uses LibSDL as the video and input library. There is good support for software rendering (without OpenGL) as well.

glHack is just one of the many NetHack front-ends. Others include the original text-terminal (TTY) version, one for the X Window System, and one for GNOME called GnomeHack.

See the official NetHack website for complete information about the actual game.