Utility, by 
The tool, in a nutshell, does what it promises to do, and what it promises to do is useful. So it’s a good tool, and if you would like to ensure the integrity/completeness of your JJ2 folder, this can help you do so.
I think it could go a bit further in offering extra help and doing so would elevate this from ‘it does what it promises’ to ‘this is a really nice tool’. For example:
- Also scan the Cache folder by default, or include it as ‘Additional Folder’ automatically if available in the selected folder, since JJ2 uses that folder as well and in many cases the tileset may be in there even if it is not in the main folder.
- Allow sorting the results by tileset filename
- Perhaps add a link per missing tileset to (for example) Jazz2Online’s search so you can download the missing tileset easily
- Look in the registry to automatically fill in the Jazz Jackrabbit folder as the default setting
- When scanning multiple folders, cross-reference results, so I can see if (for example) a tileset is missing in my 1.23 folder but available in my TSF folder
- Add a button with which one can then move tilesets around so they are available in all folders that need them
Right now the tool offers the base functionality to do what I listed above manually. This is useful, but the tool could also do it for you, and that would make it even better.