Fast flashy and not much more...
That being said it's a classic duel joystick shooter. Controls are simple to pick up and while there are upgrades to all the primary weapons for each of the four characters they are each unlocked based on a total score earned. In other words even if you only play one class you will unlock all the different weapons for all the others as you hit the different tiers of points required. There are also two perks that can be equipped per character but the bonus gained don't seem to add much to the game play.
The artwork on the characters and the enemies is well done and as mentioned before the weapons all handle about how they should.
The sound is forgettable but seems to match the setting for the most part. A narrator pops in to tell you how to knock out each objective as you clear each section.
The main down point is the check point system should be activated after each difficult section but it seems more often than not you'll complete a difficult section only to go into a second one with the check point located after as if to taunt you.
Overall I enjoyed the visualization of one of my favorite SciFi universes and the simple game play but with no real attempt to tell a story beyond, blow up or many people die, the game felt a little shallow. I'd definitely recommend it to any fan of the 40k universe though!