NetHack 4 is a NetHack fork, created by combining AceHack and NitroHack. The "4" is part of the name, not a version number, and underlines the variant's aspirations to succeed vanilla NetHack 3.4.3.
A public NetHack 4 server is available; it can be accessed via telnet nethack4.org or ssh firstname.lastname@example.org (login "nethack43", password "nethack43"). The source code repository is http://nethack4.org/media/nethack4.git
NetHack 4 can also be played (and compared with many other nethack variants) on the public server Hardfought.
NetHack 4 was originally announced on April Fools' Day 2012 as the last announcement in a series of three on rec.games.roguelike.nethack:
- UnNetHack 4.0.0, announced as NetHack 4.0.0
- A development version of GruntHack, announced as NetHack 4.1.0
- A development version of NetHack 4 (possibly to be released as version 4.2.0 in the future), announced as NetHack 4.2.0
Despite the presence of "NetHack 4" in all three of the announced release versions, the project is unrelated to UnNetHack and GruntHack.
There have been two releases since, both beta versions; 4.3-beta1 was released at the end of May 2014, just in time for the Junethack tournament; and 4.3-beta2 was released on 2 April 2015, just after the April Fools' festivities had died down.
The following is a list of differences between NetHack 4 and generic NetHack 3.4.3. Most changes are focused on the game interface and the organization of the source code rather than gameplay.
A full list of changes against NetHack 3.4.3 is available in the NetHack 4 source distribution, or on the NetHack 4 website here.
- Food safety warnings. The player is given a warning if food is old enough to have turned, if it comes from a corpse which may be poisonous, or if the player is trying to eat when already satiated.
- Attempting to move into shopkeepers, vault guards, or town guards never attacks them but instead invokes the "chat" function.
- Attempting to move into peaceful monsters brings up a warning instead of attacking them.
- The monster AI has been improved, especially with regard to tracking and pets. Pets are much better at following you and will use their special attacks against hostile monsters but will generally not attack peaceful monsters.
- There is an "explore" command (bound to the keystroke "v") which can be used repeatedly to completely cover all unknown territory in the current level.
- You can write scrolls or spellbooks without failure only if their type is formally identified. Otherwise there is a chance of failure, based on your luck and wisdom.
- Most of the gameplay including the monsters and items is very similar to NetHack 3.4.3. However, the author is not opposed to changing these things in the future.
- Manual examination of the sources suggests that monsters, items, and artifacts are identical between Nethack 4 and Nethack 3.4.3
- Classic D&D Armor Class, where lower numbers are better, has been replaced with a "defense" stat that starts at 0 and increases as it improves.
- Map occupies top-left corner of screen with a persistent (sometimes truncated) inventory window, longer message history, and three-line status section on screen at all times
- Keybinding menu available in options menu allowing assignment of any key to any command
- Player can #annotate levels
- Game keeps track of heroic deeds (character levels achieved, first time visiting levels)
- Options set persist between games
- Problems with 4.3-beta2 (that will be fixed in 4.3-beta3 and are fixed on the public server):
- Mind flayers are much more likely to generate in the Gnomish Mines than they should be