My little Worms DC Asset Util is more or less complete now. It can import, edit and export custom levels, mountains, landscapes and teams, complete with previews.
A little knowledge on low-level Amiga tech like blitting, bitmap formats and word alignment sure helped with decoding the last remaining mystery bytes: Oh, these two bytes always contain the bitmap height shifted 6 bits to the left – must be a BLTSIZE expression!
Once the last lingering bugs are squashed, I’ll publish the source somewhere. (It’s already in the page source for now, as an HTML/JavaScript one-filer.) I’ve also put together a documentation page for the various file formats.
Unfortunately this means I now have to continue with the original goal and produce a nice level map, in the hopes that it will be nice enough and in time for inclusion in the upcoming Worms DC 1.5 release end of January. :)