I made it to the Compound Level (8? 9? Can't remember) and chose to put the W on the empty space. I didn't even think about the interaction before pressing Ctrl+W, and it closed the tab! That had me laughing. If that was the final level, bravo! Very fun puzzle game. If that was unintended, an easy fix would be to swap it as W+Ctrl doesn't do the same thing. Hilarious though. Well played!