The game is "Cirno Training" and it is at first glance a simple math game. The trick to it, however, comes from the fact that Cirno, of Touhou fame, is an idiot.
The game itself is simple. You will be given a simple addition of two numbers, and two answers to choose from. Answer INCORRECTLY, unless the answer is ⑨.
You get points based on how quickly you answered, up to 5 per question, and it continues to get faster and faster, necessitating faster answer times. My personal record is 287. How far can you get?