2004 competition entry. The Omni-Arena is a large gladiatorial style arena with a twist. The fight begins within a rather confined area and only basic weapons such as crowbars and pistols. After 2 minutes of battle, the walls lower and the rest of the arena becomes accessible, along with more powerful weapons. A while later, doors open the way to corridors around the arena containing advanced weaponry.
Also, there is an all-weapons-barred spawnchamber, thwarting any spawn-campers from taking advantage of you. From there, pick a teleporter to be transported into battle.