Make it and then name it (it will be easier)
It's easier to come up with a name when you've got the game to a playable state. If you're using an engine that wants you to give the game a name as the first thing, just use whatever the theme makes you think of, and you can change it later, when you've made the game. Coming up with sub-themes within the theme might be a good way to come up with an initial name, which you can change once you've made more of the game