With 2 minifigs and a movable, working catapult, I'd give it good playability marks. As a parts set, its great, especially for the cost. As far as design goes, though, its terrible. The catapult arm stuck on the side: awful, and as others have said, its a goofy collection of colors.
The good outweighs the bad in this set, so I'd give it an 8/10.