It's a serviceable downloadable game, but your brain will rot while playing.
You're a Space Marine and there are Orks that need to die, mix in some 'Nids and there are you enemies that will die in showers of blood.
After picking what chapter you want your Space Marine to be colored (there is a distinct lack of the Raven Guard) and what class to play as, you're thrust into an Ork ship and sent to destroy it from the inside. You can play as the ranged Devastator, the balanced Tech Marine or the melee focused Liberian or Assault Marine.
Played as a twin-stick shooter, Kill Team is beyond simplistic. The most you'll ever have to manage is where to throw a screen clearing grenade or when to activate your unit specific special that can do massive damage. Grots coming at you from behind? Flick the right analog stick in their direction and your Space Marine will turn and fire his ranged weapon. Push the X button for a powerful melee option, sadly there are no combos to pull off. There's beauty in simplicity but this game devolves into just mindlessness after the first five minutes.
Being a tremendous fan of the Dawn of War series, I couldn't help but notice that the character designs are lifted wholesale from DoW 2. It's not a terrible looking game, but if this were released back during the PS2 days I wouldn't bat an eye at it.
There's really nothing else to say. At $10 it's not a terrible waste of money nor is a great use of it. I'd say to save up an additional five bucks and get Renegade Ops instead.