Mobile games:
Auditorium – http://www.cipherprime.com/games/auditorium
AVSEQ – http://www.big-robot.com/2012/01/22/all-about-avseq/
Blek – https://itunes.apple.com/gb/app/id742625884
Circadia – https://itunes.apple.com/gb/app/id489615659
Groove Coaster – https://itunes.apple.com/us/app/groove-coaster/id442689429?mt=8
Halcyon – http://www.halcyongame.com
Luxuria – https://www.youtube.com/watch?v=Z6RXlsiXXOo
Osmos – https://itunes.apple.com/gb/app/osmos/id382991304?mt=8
Pulse – https://itunes.apple.com/en/app/pulse-volume-one/id432667443?mt=8
Wave Trip – http://www.creativeapplications.net/games/wave-trip-generative-music-combined-with-familiar-gameplay-by-lucky-frame/
Other platforms:
Bit.trip Beat – http://store.steampowered.com/app/63700/
DYAD – https://www.youtube.com/watch?v=iVWOAXum75k
Maimai – https://www.youtube.com/watch?v=Kzn6BFOGmKg
Rez – http://en.wikipedia.org/wiki/Rez
Sound Shapes – http://www.creativeapplications.net/games/soundshapes-by-queasy-games-now-available-for-ps-vita-ps3/
Splice – http://store.steampowered.com/app/209790/
Not exactly sound games, but interesting design with sonic possibilities:
Dots – https://itunes.apple.com/us/app/dots-a-game-about-connecting/id632285588
Folt – https://itunes.apple.com/gb/app/id823039529
Hundreds – https://itunes.apple.com/us/app/hundreds/id493536432?mt=8
Strata – https://itunes.apple.com/us/app/strata/id641702337
Threes – https://itunes.apple.com/gb/app/threes!/id779157948?mt=8
And many other “sound toys” that point towards gaming….
(thanks to André Carrilho for many of the suggestions here)