To make things interesting and a bit more competitive, I've introduced point mulitpliers in the drills. When you're shown a drill, you'll see a multipler count-down. If you answer the question quickly, you can get up to a x5 multipler on that drill's point worth! The minimum you'll receive is a x1 multipler, so you'll always score points if you answer correctly.
The other side effect of this is that if you answer the drill quickly, then the interval for that drill is increased by the multiplier. This means if you answer it quickly, we'll ask you the same drill farther out than usual. This helps adapt the system better to drills that take very little time for you to answer due to it's ease.
The question is...is it freaking people out? Is it a good thing? A bad thing? Does it make it more exciting or does it make you go into a tailspin?