Actually, your game does not even work in non-strict mode. I turn the game on and click RE/Start and it lights up and plays a tone for the first round. I click on the correct button and the console shows “wrong” and the game keeps lighting up the same button and playing the same sound, no matter how many times I click the correct button.
You should thoroughly test out your game to see all the issues it may have right now. I did not have time to review all 248 lines of the JavaScript to figure out why the above happens. When you narrow down where you think the problem is and still have questions, reply back to this same thread with a very specific question about code you think you work one way but instead does something different and we will try to help point you in the right direction.
At this point, you need to figure out the basic play mode first.
Another issue I noticed is that the button lights up first and then plays the sound instead of both happening simultaneously.