I think these CSS learning games would work better if the game you were trying to complete was something you would actually use the technology for. For example,

I think these CSS learning games would work better if the game you were trying to complete was something you would actually use the technology for. For example, a game that involves building a website. (e.g. Instruct me to make the page for UX friendly by moving an element from one column to another, or adjust columns, etc.) I would never use CSS grid to do what this game is asking me to, so even though it helps me learn the syntax and properties, it's not helping me learn how it's going to be applied to an actual website.