Resistance 3's Brutality Pack puts you against the Grims.

Entitled the Brutality Pack, the $3.99 expansion brings Horde-inspired co-op to the bleak shooter's roster of modes. Faced with a never-ending stream of Grims, you'll need to keep your cool in an overcast Wales to stem the threat.

The expansion pack will see the sledgehammer added to Resistance 3's multiplayer component for the first-time, but sadly won't include any additional trophies.

To accompany the violent atmosphere of the Brutality Pack, Insomniac's signed up heavy metal band Mastadon to provide the score. Three songs from the band's latest album will be included, in addition to two instrumental tracks.

It definitely sounds like a big update for the asking price. Hopefully Insomniac will expand the mode further if the feedback is good.

The Brutality Pack is due out on the PlayStation Network this week. You can catch the game's debut trailer through here.