Lucid
11 Achievements
6-8h
Steam
BLUE_SKIES
Clear 18 BLUE blocks in consequent moves.
31.1%
How to unlock the BLUE_SKIES achievement in Lucid - Definitive Guide
If you haven't already unlocked this there are the required number of blocks on screen at the start of Level 30. Just clear from the top of the screen down so you don't separate any blocks.