Studio Pixel, the one-man development studio behind the original Cave Story, has created a new game for iOS called Azarashi, available on iTunes now for 99 cents. It's an exceedingly simple game: you tap to catch three seal keychains as they fall, and your reaction times are added up to form a score.
What distinguishes Azarashi from other iOS microgames is Pixel's fantastic artwork, which delights with cute seal keychains and happy cat trophies. Just don't ever tap to catch a keychain too early. It abruptly becomes less cute.