Not sure how this fits the "shock" theme.
This could have benefited from playtesting. After realising I was incorrectly trying to unfill the tiles rather than fill them (my bad), I managed to fairly quickly finish level 14, which then forever loops on 14. I noticed the level select has a button for level 15 that goes to 14, and then it has 35 more unclickable buttons of which 34 of them say "Button" (I feel sad for the lonely button with no title!)
I think the font antialiasing also invalidates the 2-colour requirement.