Dunno how true this specific statement is. Bullet hell shmups like DonDonPachi and Touhou are mega popular there.* Rhythm games too.
*I know Touhou is popular because of the cute girls, and DonDonPachi too, but the actual bullet hell scene is still massive there!
Huh. Wonder who that could include. Can't be me obviously.
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Oh, and on the topic of shooters, Splatoon 3 (which I know isn't an FPS, but I think is still relevant) sold nearly 4 million copies in Japan, making it the best selling game there of 2022 in a matter of a month. Clearly there is a market for shooter games.