lemsopA level editor of Prince of Persia for the Master System. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
DownloadThis is an ALPHA version. It is not yet
feature-complete and contains BUGS.
My apoplexy level editor uses a similar GUI.
See its instructional videos.