Okay take a look at this image. I played the game about 5 minutes ago and got this. (that was on the hard setting)
The score equates to 405 mouse clicks
Now considering I am playing on a laptop and it is not on the most stable of surfaces i.e. it is hanging off the edge of a table and all I have is the touch pad and the two wee buttony things. Maybe my score has something to do with that some games I've played e.g. Final Fantasy 8 where there is some rapid button push required, helps me.