Make a game about trying to buy something in the store.
You need to exchange one thing for another thing.
Consider your variables, and alternative strategies the player might take to achieve the goal beyond just money.
You have 10 minutes.
Make a quiz.
It could be a character quizzing you, some kind of challenge or personality test.
You can use stat as a score.
You have 10 minutes.
Start with a lot of something, and lose it over the course of your game.
You have 10 minutes.
Use two different sorts of stats in your game.
You have 5 minutes.
5. It is as if there were 2 stats
5/100 for Blake's 100 games later