I don't know if you still check these or if the bug I found is fixed in the steam version, but by pressing and holding left to push a block and then pressing right just before the block actually moves, I was able to push blocks through walls. Here is a screenshot:
This damage to the level persists even after restarting the level and going back to level select. It seems like it might have to do with how you're handling the direction the player faces based on keyboard input and how that relates to the block pushing logic. I was not able to reproduce it going in the other direction.