Just completed a prototype for Weekly Game Jam #147. The theme was "invisible". What we came up with was a space adventure where you must reach a base, but the base is cloaked until a certain objective is met. We had lofty goals and only produced a subset of features we wanted within the time constraints, but the MVP is a fun vignette.
Game on Github.io: https://bentok.github.io/invisible/
Itch.io entry: https://sir-bentok.itch.io/space-jammin