Falcon's Eye is a version of computer game NetHack which introduces isometric graphics and mouse control. Falcon's Eye has been praised for improving Nethack's visuals and audio to an almost commercial level and has been noted as among some of the best free games available by Linux Journal.
Falcon's Eye was developed by Jaakko Peltonen, a researcher of neural networks at Helsinki University of Technology, originally as a separate engine, and then grafted onto Nethack. The artwork and sound effects are largely his, with some submissions from users. Nethack's code assumes little about the user interface, telling which dungeon maps and messages to display, but leaves the implementation details to the interface. Peltonen explains that this versatility helped him to create Falcon's Eye, as he did not have to work around a fixed character-based interface.
Since the release of version 1.9.3 in 2001, development of Falcon's Eye has not progressed, with the game based on a now out-of-date version of NetHack. In the interim, at least one unofficial update has appeared in the portage package management system. This level of inactivity prompted the forking of Falcon's Eye to create Vulture's Eye which has significant improvements on the original.
Peltonen had planned to add more customization options, allowing users to add their own graphics. As some users reported difficulty in compiling and installing Falcon's Eye, he also wished to simplify this procedure. He also envisions an application for Nethack that allows a user to switch between different user interfaces, similar to software skins.
Whilst adding some features, such as a path-finding tool, Falcon's Eye doesn't alter the Nethack gameplay. Peltonen says that this was to ensure that future versions remain compatible with future releases of Nethack.