Brace Yourself Games just released Crypt of the Necrodancer on iPad and iPhone.
The Pocket Edition as they call it supports multiple control schemes and is playable on both iPhone and iPads running iOS 8 and above. You can buy it here. It costs $4.99 or the equivalent on your iOS App Store. The Pocket Edition, just like the PC version, supports custom soundtracks from your music library. The included 4 soundtracks are pretty damn amazing already. Check out our review of the PC version here.
Crypt of the Necrodancer is available on iOS, PC, PlayStation 4, and PlayStation Vita.