Mean Girls is an exercise in bad Flash animation if I ever saw one. True, if you add movement to graphics, it usually adds interest, but there's nothing more than a standard left tilt or a right tilt applied to certain body parts. So you've basically got everyone tilting their heads or their arms back and forth the entire game. The artwork also commits a few crimes against anatomy. It's either that or some of the characters in the game had growth spurts in random places on opposite sides of their bodies. There are some interesting character designs, and there are a few highlights in artwork, but it's inconsistent at best.
There's a pop-rock song titled "Wise Up" by Kay Hanley and Jonny Mead in the opening sequence of the game. The rest of the game's soundtrack is less than memorable generic rock and techno beats. Characters make exclamations and say short lines during fights, but other than that, there is no voice acting in the game.