The number of puzzles and collectibles within the game give it a longer lifespan. Even after completing the game you'll find yourself running back through the levels in Free Play to pick up artifacts. Collection lego pieces allows you to unlock additional characters and other bonus items, as was the case in Star Wars.
There's little more to say about this game which hasn't already been said here. There's nothing wrong with Lego Indiana Jones but Total Gaming do wonder when the bubble will burst for TT Games.