Not Enough Fun

There's this little flash game I've become quite entertained by as of late. It's called Desktop Tower Defense.

(If you click here you'll never make it through your homework again... I promise! Fair warning...)

Basically you set up little mazes and cannons to blast little blobby "creeps" as they try to move across the screen. I've beaten the Easy, Medium, and Hard levels, but I'm struggling on a few of the Challenge levels.

So when I get tired of trying the Challenge levels over and over again, I try one of the Fun levels. Well, apparently in my last game I didn't have enough fun, because here's the screen after I lost.