The game begins with the default laodout; the Sledgehammer, as the rounds progress weapons will appear allowing the player to have a full aresenal of Resistance 3 weapons. Occasionally the rounds will state how the Grims have upgraded, either in numbers, attack, or health. Combos will help the player advance through each level by giving a "power-up", such as a 10 combo, which will restore health. The Grims spawn randomly each round depending on the player's location. In Co-op, the second player will play beside the first player, when a weapon spawns however, there will be two for each player in certian buildings. More weapons will also spawn to replinish ammo. Also while the rounds are being played you can listen to seven tracks from the band, Mastodon.