The walls you leave behind

A short puzzlescript game where the player leaves behind walls with every step  but blocks can be used to destroy them.

Mobile friendly version: https://www.puzzlescript.net/play.html?p=bc4d6ab178418fbce41ef37259bfadff

Source code: https://www.puzzlescript.net/editor.html?hack=bc4d6ab178418fbce41ef37259bfadff