I'm disappointed. So often people just stick to the first theme they came up with and never try anything else for their game.
Numerous times I've made student and companies play around with their theme and forced them to change and try other themes.
Guess what! In many cases they have been happier with the new theme and stayed with that, even that they have said first that "No, we have the best theme ever!"
Ok, you have a game where you are a fruit, like a banana. Then the banana shoots with a shotgun.
What? Why doesn't the banana shoot banana peels? This would match the item, the theme and utilise the theme!
It would even be more fun and people might expect that and not a shotgun.
When you have the right, it just won't come off.
Theme for Tetris?
First idea was that the pieces would be creatures. Second theme and idea was that we'd be building a tree.
Most logical is the City building where the blocks are actual house blocks. It's more intuitive and obvious.