ZQuake is a QuakeWorld engine with moderate enhancements compared to other source ports and is being used as base for FuhQuake and subsequently ezQuake.
Squidge solved the last ZQuake issue, and now yoyo has refined it all very nicely. So get Zquake, ZDoom and ZHexen over at yoyo's site
# Client and server in one binary - the way it should have been from the start
# Win32 priority fix in zqds - you can play with ping 13 on localhost now, and you don't need priority.exe any more!
# All known qwsv security holes fixed
# Highly tweaked & bugfixed networking/prediction code
# More bindable keys, like capslock, numlock and keypad keys
# Powerful scripting system
# FPS settings menu - you can bump your fps considerably by removing annoying gibs/corpses/torches, etc, from the screen
# Teamplay messages (%h, %a, %l, etc), with support for qizmo .loc files
# Playback of Qizmo .qwz demos
# Playback of NetQuake .dem demos
# Demo player menu
# Fullbright colors and colored dynamic lighting in GL
# [hacky]lightmap overbrights in GL
# gl_gamma and gl_contrast cvars - you don't have to adjust your monitor's brightness every time you want to play Quake :)
# A number of renderer speedups (both software and GL), ZQuake runs roughly 10% faster than QWCL 2.30
# Tons of bugfixes all over the engine
# Single player and coop games.
# Ability to save and load back single player games
# And much more...
Download the executable and unpack the .zip file. Place the .prc into /Palm/Launcher of your memory card. Place the .zdk into /Palm/Programs/ZQuake of your memory card. Now you need files from the original Quake 3D. You can also use the files from the demo version. Place the ID1 folder into /Palm/Programs/ZQuake of your memory card.