Osu? Has a mode called Osu!Mania. https://osu.ppy.sh/home. Source: about 1 year ago

You can play on osu! (it's free and has a Taiko mode too) and get the sounds here: Idol (TV Size) and Idol English Ver.. Source: about 1 year ago

There are currently 2 different rank leaderboards: one for the stable client and one for the lazer client. The osu! Website shows rankings of the stable client while lazers ingame profile viewer shows the rank you achieved in the lazer client using the osu!lazer website. There are fewer people playing osu!lazer than the stable version which is why your rank is higher. Source: over 1 year ago

(Also Elite Beat Agents/Osu! Tatake! Oendan! Are fuckin' great for any skill level, but if you don't feel like digging out your DS I'm just gonna shill the freeware clone osu! instead.). Source: over 1 year ago

IIRC OSU! Has remarkably low system requirements. Source: over 1 year ago

If you still want an estimate you can check on Steam Spy. Source: about 1 year ago

I think Valve will shut it down once it learns about the monetization. AFAIK that is what happened to https://steamspy.com/ when they introduced paid subscription tier. - Source: Hacker News / over 1 year ago

If you still want to see numbers, you can try with Steam Spy with VN available on steam. Most of the developers say that those numbers are false. Source: over 1 year ago

Research popular game genres, for example on https://steamspy.com, and find a genre that currently sells well. Source: almost 2 years ago

Steam Spy - must have tool for anyone who wants to get some data about Steam games. Source: almost 2 years ago