Ai-chan's 17th single or 18th since it's a double single, well...whatever you wanna count that to be.

First track, Rocket Sneaker is an upbeat, fast song, almost cheerful and expresses carefree mood. I still can't help being a bit annoyed by her airy voice, like there's something hollow in it, or is it the way she's singing it. Nevertheless, it's not bad. I liked the ending parts where it's mostly instrumentals with the guitar riffs and piano.

Second track, One x Time---->Piano plus clapping in the beginning, this is a slower track, but not a ballad. Laid back track but i wont listen to it on repeat though.

Third track, Sora to Kujira (Sky and Whale) ---->Acoustic guitars accompanying her vocals, another slower track.

The other two tracks are just the instrumentals for the first two tracks.

Overall: 6.5/10

I'm a bit disappointed by this single, even having a third track can't really save this single from being on the down side. It's like ups and downs with Ai Otsuka, really. sometimes she comes out out with fabulous tracks, then afterwards, she comes out with very typical tracks, which doesn't stand out.