I liked that if you get the answer wrong, it shows it as red, before you release the click button. It gives you insight on how what you  thought was wrong. Plus, you can see what questions you may have gotten wrong at the end, by the screens showing what the actual answer was.

I only disliked that there was no explanation given as to why the answer was right, or wrong. I understand that is not necessarily needed, but it would have helped some who wouldn't understand.

Great job, nonetheless!