It sounds like a five year old singing, the voice is cool but sounds weirdly childish

Sake Monster☆RaiRai!! 【Shinra-bansho】

【東方ヴォーカルPV】こ～んさるたん！Akatsuki Records

Original track: Beloved Tomboyish Girl 
Arrangement: ARM
Re-arrangement: void
New vocals: Miko
Original vocals: Chiyoko
Album: PUNK IT! TOUHOU!

COOL&CREATE'S U.N Owen Was Her Remix...

Original Song (U.N. Owen Was Her?) By ZUN, remix by COOL&CREATE.