Fly a rocket from launchpad to endpad. The route between them is the problem — obstacles stack up, the margin for error narrows, and the run is a test of how precisely you can handle thrust under pressure.
What I did
Wrote the game design document covering mechanics, narrative, and design decisions before building
Storyboarded the game end to end, mapping how the experience progresses stage to stage
Designed every level, pacing difficulty so the challenge builds without spiking
Built the rocket and movement systems in C#, which set the feel of the whole game
Writing the design document first is the habit I carried into Fearfobia years later. Deciding what the game is before building it is the cheapest problem-solving available.