This is Antarctica Act mod for Unreal Tournament 2004.
"The year is 2050. The world's supply of oil is running out. Antarctica has become one of the last places in the world with a good supply of oil. All over the area western countries and their allies have built bases so that they can extract the oil and securely move it. But these sites are being attacked and taken over by a terrorist organisation. They are demanding ransoms for these facilities. The goal of this level is to train for an assault on a base that has been captured by the enemy. As your team already have plans and pictures of this location, they have virtually recreated it so that the player's team can know how to fight and what the enemy's tactics will be in the snowy terrain. The player must complete 4 areas in order to win the round. They then play as the enemy with the aim being to defend the base." Visit Matthewbaxter.co.uk for more info.