dlsite link: http://www.dlsite.com/maniax/work/=/product_id/RJ040587.html
Release date: 2008/07/29
VNDB: https://vndb.org/v7791
Circle is also referred as でふつ屋 (?) defutuya
ancient game...I vaguely remember playing it before, or maybe it was the prequel...I am not sure anymore; Saw some links...