Posted October 10, 2018
Correct statement would be: 'Recent versions of WadSmoosh work only on GZDoom (or QZDoom); they do not support old ZDoom without few extra actions'.
AmethystViper: Another thing I forgot to mention about WadSmoosh is that it only works on GZDoom (or QZDoom); it does not support old ZDoom.
For example, WadSmoosh release dated 2016-08-11 works perfectly even with ZDoom v2.7.1. Unfortunately it looks like author of this very handy tool provides only the latest version as a complete download for the end users.
So, the easiest way to get old ZDoom compatibility is to open the pk3 built by the WadSmoosh with your favorite archiver and remove menudef.txt lump. Visit official issue tracker for the details: https://bitbucket.org/JPLeBreton/wadsmoosh/issues/11/backwards-compatibility-with-zdoom#comment-42600363.
Alternatively, you could extract one of the former snapshots from the official repository. But that's is definitely a hard way, which requires some technical experience. And latter improvement of the code would be lost as well with such an approach.
Post edited October 10, 2018 by Schwertz