Here is the full list of all 165 OxU achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Open level Q
Pass the level P
Rotate the floor with cross line
Open level P
Pass the level O
Open level O
Pass the level N
Open level N
Pass the level M
Open level M
Pass the level L
Open level L
Pass the level K
Open level K
Pass the level J
Open level J
Pass the level I
Open level I
Pass the level H
Open level H
Pass the level G
Open level G
Pass the level F
Open level F
Pass the level E
Rotate the floor with T-line
Open level E
Pass the level D
Open level D
Pass the level C
Open level C
Pass the level B
Rotate the floor with angle line
Open level B
Pass the level A
Rotate the floor with straight line
Open level A
Pass the level Q
Pass the level R
Pass the level S
Pass the level T
Pass the level U
Pass the level V
Pass the level W
Pass the level X
Pass the level Y
Pass the level Z
Pass the level 1
Pass the level 2
Pass the level 3
Pass the level 4
Pass the level 5
Pass the level 6
Pass the level 7
Pass the level 8
Pass the level 9
Pass the level 0
Pass the level !
Pass the level ?
Pass the level #
Pass the level $
Pass the level [
Pass the level ]
Pass the level -
Pass the level +
Pass the level =
Pass the level {
Pass the level }
Pass the level /
Pass the level \
Pass the level ⬤
Pass the level ▩
Pass the level ✓
Pass the level 🌙
Pass the level ⦾
Pass the level ⚙
Pass the level △
Pass the level ⬛
Pass the level 🌣
Pass the level ◯
Pass the level ⬡
Pass the level 💜
Pass the level 💥
Pass the level 🟎
Pass the level 💠
Pass the level ★
Pass the level 🛇
Pass the level ⊞
Pass the level ⭗
Pass the level 🌐
Pass the level ☢
Pass the level 🞓
Pass the level ☘
Pass the level ❄
Pass the level ❖
Pass the level 💧
Pass the level 💡
Pass the level 🏆
Spend more than 10 minutes on any level
Pass laser through the portal first time
Destroy Companion Cube
Touch the Companion Cube
Aim the laser at the Companion Cube
Pass the game!
Open level R
Open level S
Open level T
Open level U
Open level V
Open level W
Open level X
Open level Y
Open level Z
Open level 1
Open level 2
Open level 3
Open level 4
Open level 5
Open level 6
Open level 7
Open level 8
Open level 9
Open level 0
Open level !
Open level ?
Open level #
Open level $
Open level [
Open level ]
Open level -
Open level +
Open level =
Open level {
Open level }
Open level /
Open level \
Open level ⬤
Open level ▩
Open level ✓
Open level 🌙
Open level ⦾
Open level ⚙
Open level △
Open level ⬛
Open level 🌣
Open level ◯
Open level ⬡
Open level 💜
Open level 💥
Open level 🟎
Open level 💠
Open level ★
Open level 🛇
Open level ⊞
Open level ⭗
Open level 🌐
Open level ☢
Open level 🞓
Open level ☘
Open level ❄
Open level ❖
Open level 💧
Open level 💡
Open level 🏆
Open Final level