180

Use the arrow keys to move the squares all in one direction. Any number of identically valued squares, if in a row, will merge together.

And remember, 180 = 2 × 2 × 3 × 3 × 5.

(For a bonus challenge, try getting 150 on this grid. It's harder than it looks!)

Created by gold5472. Based on 144 by Joe Zeng and conceptually similar to Threes by Asher Vollmer.