I was wondering, if it is possible to only include a few of the individual levels in a specific individual level category instead of applying the category to all individual levels. I have looked through the "Edit Game" page, but I couldn't find any such option.

Not possible unfortunately.

If you make it a subcategory-variable you can. Except you have to add a specific individual variable for every individual IL you want to add the category to. It's a dodgy work-around basically and it can be really annoying to setup if there are a lot of levels where the category applies, since you have to add the same variable over and over manually.

Thanks for the info. That's too bad. Would be a nice feature.