Here is the full list of all 500 Oik Memory achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Complete level "Check mark"
Complete level "Christmas tree"
Open level "Check mark"
Complete level "Clover"
Open level "Christmas tree"
Open level "Clover"
Complete level "Square"
Complete level "Сircle"
Open level "Square"
Complete level "Ban"
Open level "Сircle"
Complete level "Gear"
Open level "Ban"
Complete level "Heart"
Open level "Gear"
Complete level "Atom"
Open level "Heart"
Complete level "Cloud"
Open level "Atom"
Complete level !
Open level "Cloud"
Complete level ?
Open level !
Complete level "Boy"
Open level ?
Complete level "Girl"
Open level "Boy"
Complete level Z
Open level "Girl"
Open level Z
Complete level Y
Complete level X
Open level Y
Complete level W
Open level X
Complete level V
Open level W
Complete level U
Open level V
Complete level T
Open level U
Complete level S
Open level T
Open level S
Complete level R
Complete level Q
Open level R
Complete level P
Open level Q
Complete level O
Open level P
Complete level N
Open level O
Complete level M
Open level N
Complete level L
Open level M
Open level L
Complete level K
Complete level J
Open level K
Complete level I
Open level J
Complete level H
Open level I
Complete level G
Open level H
Complete level F
Open level G
Complete level E
Open level F
Complete level D
Open level E
Complete level C
Open level D
Complete level B
Open level C
Complete level A
Open level B
Complete level 0
Open level A
Complete level 9
Open level 0
Open level 9
Complete level 8
Complete level 7
Open level 8
Complete level 6
Open level 7
Complete level 5
Open level 6
Complete level 4
Open level 5
Complete level 3
Open level 4
Open level 3
Complete level 2
Open level 2
Complete level 1
Open level 1