I liked the concept of this (even though it doesnt really fit the theme) but I have a few complaints (outside of the fact that there are no sounds). Enemies spawning in front of you that are faster than you are really annoying because sometimes you just cant avoid them and you end up dying even if you knew the correct answer. Sometimes, the right answer still proved wrong and at first I thought it was just cause I answered wrong but it started happening more and more often until I was certain that it was a bug because I was very precisely keeping track of my answers. And finally the first two levels have no question (maybe they do but camera is offset to the right). Otherwise it's a nice concept, really and I still enjoyed it. It just needs some polish that's all. Good job!