I think this game's real success is in the realization that these language learning games, and generally the process of learning languages for real, is the most fun at the start, when you know the least. This seems counterintuitive, as you do feel clueless looking at these scribbles for the first time, but inevitably the association machine in your skull fires up and you can make deductions rapidly, like a kid in a candy store.

As your knowledge of the language fills in, those deductions actually become simpler and come slower, the game can't really challenge you once you can translate everything either, but then, exactly on cue you're hit with a new set of words and rules to learn, and the process starts all over again.