JGH/DefRoom
"DefRoom" v1.24 by J.G.Harston
BBC/DefRoom
"DefRoom" by J.G.Harston for BBC
JSEdit.zip
"Jet Set Editor" by Paul Rhodes
JSWCK.zip
"Jet Set Willy Construction Kit" v1.0 by Andrew Broad for Spectrum 128k
JSWED104.zip
"Jet Set Willy Editor v1.04 05-Aug-1998" by John Elliot for DOS
JSWED2
Jet Set Willy Editor v2 by John Elliot for Windows
JSWEdit.zip
"JSW Editor Mk II" by Softricks
JSWEDIT3.zip
JSW Editor by Mark Jeffries
SWAN.zip
JET SET WILLY EDITOR by Richard Swan
Jet Set Willy for RISC OS includes a game editor in the program.