Ted & Astro is a game that I worked on for an Educational Games and Simulations course while attending the University of Waterloo. The game has two main components: a gravity-based space game and a small logic puzzle.
In the space game, the spaceship only has a limited amount of fuel, so players must use the gravity of nearby planets and asteroids to slingshot to their final destination.
The logic puzzle was mostly just tacked on to meet the “educational” requirement for the project.