Anyway, Version 5.2.0-dev2 is now available for testing. Some of the highlights of this build:
* The Editor now uses the Load Level dialog for the Go To Level... and Remove a Level... features.
* Many, MANY bug fixes. Tutor levels 5, 6, 11, 14, and 18 now work (14 hasn't worked in ANY of the prior builds, so that's a significant accomplishment).
* Level files take slightly longer to load, but in exchange there is no more delay or visual clutter when opening the Load Level dialog.
* Remove a Level... in the Editor no longer always removes the active level, regardless of what you entered for a level number (that bug has also been around for a while).
The build can be downloaded from the usual place: http://lasertank.worldwizard.net/prereleases/prereleases.html