Man I did not realize how bad I am at my times tables these days (and some other basic arithmetic...)
I think my favorite moments in this game were when it got really intense and I had to clutch an answer in a small number of seconds. This did make it somewhat frustrating to replay the rest of the game to get back to that point. This is for two reasons: 1), the rest of the game is not too hard, so it is less engaging, and 2) all the players come back to life, making it take much longer between when you get to actually do something. I was always hoping some players would die early--not so that I could win, but so that I could stay more focused on the game, sorta.
Still, I did actually lose relatively often during the "long time period" part of the game, so I think it was an important part of the difficulty. It forces you to hold on through a somewhat grueling section and then gets really tense, and this does hammer home the tension for sure. You really don't want to lose your progress once you get into the endgame.
The use of arithmetic as the actual challenge is very effective, I think. Arithmetic is something I do sorta know, but not perfectly, and it is also a skill I do use in my day-to-day life, so it is sort of the perfect thing to ask me to do under time pressure as a game. I suppose "timed arithmetic challenge" is a somewhat common kind of math game, but as I said, this one really does hammer home the tension, which I think makes it decently unique. It makes it really very satisfying when you just intuit the correct answer under the time pressure and live, and then it makes you feel like an absolute fool when you think you knew it and instead see your guy explode. I love it.