As well as the standard ASCII interface, many official and unofficial graphical user interfaces are available. This page will be a visual showcase.
All of the status values except turns elapsed flash green when they increase and red when they decrease - so since I just went up the stairs to Sokoban, level is red, and since I just picked up some gold and am recovering power, those are green.
By using F3, F4, and F5, the user can switch between this view, another with narrowed tiles that makes the entire map visible, and one using IBMgraphics.
Noegnud is a semi-3D interface for both NetHack and SLASH'EM.
NetHack 3D features a first-person view and supports both English and Japanese.
The NetHack Curses Interface is an alternate character mode interface with many features not present in the traditional tty interface.