There are always a lot of opinions on if a theme is good or not, I am curious what criteria people use to call a theme "Good".

For me, there are a few criteria.

1. The theme needs to be workable for the following game archetypes: Platformer/Movement, Incremental/Factory, and Puzzle. This is important to make sure that there are enough ways to interpret the theme that people can make a variety of games. I also don't want someone who really likes making a particular genre feel like they can't participate.

2. The theme should be more than just set dressing. Some sort of concession should be made mechanically to accommodate the theme. It is fine if using it as set dressing is an option, it just can't be the only/primairy option. I want there to be pressure to make something with gameplay that is unique to the theme and just swapping out art doesn't really do that.

3. The theme should be simple, a common phrase or under 3 words. This makes it easy to convey and helps avoid the overly narrow/limited interpretation issue.

4. Not required, but gets bonus points if the theme has some sort of double meaning

I find a lot of themes are able to meet these rules, but some do a better job than others. Any genre specific theme is automatically out, and so are all the art only themes. What rules do you follow ?