How does a game teach Chinese typing?
Chinese typing practice is training the reflex that turns a meaning or sound into the pinyin string you type on a keyboard — exactly what you do when texting in Chinese with a pinyin IME. Recognising a character isn't enough; you only really use it once you can type it fast.
The word-waterfall game drills precisely that: hanzi with their meaning keep falling, and you must recall the pinyin and type it within seconds before the card hits the water. The time pressure turns typing pinyin from something you think about into a reflex.
Arcade scores and coins are stored separately from your study progress — play to train your hands without diluting your HSK path or the study leaderboard.