Slightly disappointing, lack of depth.
But the game lacks the depth to make it worth $50. Realistically, you can beat the original campaign in 10-15 hours. Endgame after this is 5-10 hours of replaying levels looking for secrets and building up skill to reach the jedi master rank. Roughly 15-25 hours of gameplay depending on how well you master it.
After beating the game, you can spend some time messing around with the bonus levels that are unlocked. Also, progression in the campaign unlocks extra multi-player characters and levels. Multi-player is fun and fast-paced, but soon grows tiresome and repetitive. Fun for birthday parties or friendly get-togethers, but not much else.