Quake3_Quake1 playable single player demo available:
This Quake 1 single player mod makes DarkPlaces / Zircon feature available for mapping with a QuakeC implementation of numerous DarkPlaces capabilities.
Install: Unzip to your Quake 1 folder to quake/quake3_quake1 like any mod.
Startup: darkplaces.exe -game quake3_quake1 or zircon.exe -game quake3_quake1
The Quake 3 map format means texture resolution has no specific limit, that models can collide of a variety of different sizes and that it is easy to create rotating brushes (doors, cabinents, ramps) and additional models of md3/obj/ase can be compiled as part of the map (see the bathtubs in the provided map hotel1).
The 2 single player demonstration maps illustrate capabilities like rotating doors, emitters (you can make your own in effectinfo.txt and specify it in the map editor), func_text, npc text dialog, books, mechanical contraptions, keypads, radios, attachments, a quick vehicle interaction, barriers with feedback, usable items/buttons, custom finale text. The monsters, items and weapons are with few exceptions higher resolution.
The download is available. This is a mapping kit as well with models/textures/sound. The J.A.C.K. and TrenchBroom .fgd files are being finalized/tested and will be available as time permits -- a few days is likely.