And I thought SR3 was disappointing...
Aliens do not fit into this game at all. I miss the over-the-top yet still grounded nature of SR2. SR3 went too far as it is, SR4 is just...yuck. The jokes aren't even particularly crude or offensive, just dull. I chuckled less than a dozen times, which is pretty bad for a game built on humor. And I have a freakin' doctorate in humor, so I know what I'm talking about!
The shooting lack omph, and the car physics feel all wonky (even if the controls are good). Not that you need to bother with any of them much with your overpowered superpowers. They were okay in the DLC for SR3, but here they actually take away from the game; it just doesn't fit, and grinding everything out is a chore. Everything feels rushed; you can really tell this game was made in less than 2 years. To top if it off, the gameplay quickly settles into repetition, and becomes boring.
In short: this is a bland and pointless addition to the saint's row universe. While it's perfectly playable, it's not all that much fun to play. If you are thinking of getting it, wait for a hefty sale and buy a better game now instead. I hear GTA V is coming out soon...?