A lot of the equations and answers are very poorly set out, sadly.
Also, the game itself is very ... Flat, and lacks substance.
The biggest problem is that several of the equations are very hard to interpret. I have run into some confusing questions and equations before, though my experience is primarily in real analysis and calculus -however, I can say that, were you to give these questions to most that I have spoken to, they would ask for clarification.
So to summarise, I would advise giving it something of a background - subtle, but not so blank. Clear up the equations and ask more succinct questions, and maybe touch up the layout.
I do admire that you put out a maths flash 'game' though -- that's rather refreshing! ^.=.^