Crypt of the Necrodancer is a roguelike-like dungeon crawler where you move across tiles to beat down on enemies with the twist being that you have to do so in time with the music that plays. Every stage has it's own track and each enemy has it's own behavioural pattern for you to learn.
The game has been out on PC and PlayStation consoles for a while, but now it joins the Apple family, as it has been released on iOS. It's the same game in it's entirety, albeit now with a control scheme custom built for mobile.