This past Thursday marks the first day I've ever given a midterm, and the second time I've had anything resembling a standard written exam.
It's much harder to make a written exam "game-like" without having rules that are so confusing that they get in the way of evaluating students' mastery of the material; the best I could hope for was an exam where students found the questions interesting and thought-provoking. (This meant essay questions. Lots and lots of essay questions. 18 of them, to be precise.)
Mostly, students complained about a two-hour written exam due to hand cramps. They can play video games with an ergonomically-destructive N64 or GameCube controller for ten hours straight, yet two hours of writing and they've suddenly got carpal tunnel. I don't get it.
Having never made an exam like this, I was afraid that it would be too easy, or too hard, or too short, or too long. As it turns out, it looks like I had some serious beginner's luck; no one ran out of time but most students stayed nearly till the end, and so far it's looking like the grades will fall on a nice bell curve. If I've made a serious mistake, it's setting myself up to grade 18 essay questions for 23 students over a single weekend (which is, honestly, much more writing than two hours on a single exam). No hand cramps yet, even with playing Guitar Hero during breaks!