Here is the full list of all 12 Olimdal achievements.
Reach end of Room 2 under 20 seconds
Reach end of Room 25 over 5 minutes
Destroy any movable object
Rotate camera 360 degree to any direction in Navigation Room
Try jumping over end of room from upper staging
Figure out solution of first part in 15 seconds and reach end of room in 1 minute in Room 14
Reach end of Room 7 with an alternative way
Survive from a dangerous situation
Enter library tower Olimdal
Spend more than 1 minute in Room 23
Reach Construction Room before Release
Reach end of Room 12