The last level doesn't complete. Everything was in the correct position, but nothing happened.
Viewing post in A Job with Boxes jam comments
Have you downloaded the game around the first two hours it was uploaded?
Since then, I patched a few bugs including the last level not completing.
The www folder contains the game's saves - try downloading the latest version and moving the saves into the new folder, it might work and allow you to start the fixed version from the last save point.