We have seen some confusion surrounding the theme both here and in the Brackeys Community Discord server.
I understand this confusion may largely be due to a language barrier. To clarify, “risk it for the biscuit” is an English idiom meaning to take a risk for the chance at a reward.
This could be anything. It could be as mundane as applying for a job; your risk is rejection and the reward is a high-paying position were you to be accepted. You risked it (potential rejection) for the biscuit (a job).
Having literal biscuits in your game is not required, the theme is intentionally vague so as to give everyone creative freedom. If your game incorporates risk / reward in some way, you are still aligned with the theme.
But of course, if you wish to include literal biscuits / cookies, this is fine too!
I wish everyone success in your creations, have fun!