Lemmings Level Editors
Golems
Golems is a clone of DOS Lemmings that includes a level editor. Golems runs on Windows.
Lemmix
Lemmix Level Editor is a level editor for DOS Lemmings levels and Lemmini levels. Lemmix Level Editor runs on Windows.
LemEdit
LemEdit was the first level editor for DOS Lemmings. It has been modified by ccexplore and tseug to work in DOSBox. The unmodified version will only run correctly on DOS. Customized Lemmings is a modified version of the DOS Lemmings game engine that can be used to play level packs made with LemEdit.