It's useful feedback that someone unfamiliar wasn't given enough information to understand! I might update the page later to give some more scaffolding.
If you're interested in playing more little games in this engine (or making some yourself!) I highly recommend starting here: https://ledoux.itch.io/
Ledoux made the engine and has some games that are far more complicated than this one you can try out. He also keeps a collection of other people's games on his page!