The goal in each level is to fill 70 % of screen with filler balls which you create by holding the left mouse button. But while the filler ball is growing a bustron mustn't touch it or the filler ball will explode. Each level comes with a certain amount of filler balls at your disposal and a time limit. Also, as the game progresses, there is more and more bustrons to avoid.
The graphics are simple, but well coded and designed, with real-time plasma-like moving background and few additional math-based effects. Also, the game comes with nice music (3 tracks) and sound effects.
Rise of the Bustrons is a fun time-waster, but the whole point of the game comes down to beating your own or other people's scores (the default ones are too easy to beat). When you see the first level, you saw it all.