At 6PM Monday night Microsoft let E3 judges (I’m one of them!) play a small portion of the single player campaign of Epic Game’s November 7 Xbox 360 exclusive “Gears of War 2.” Only by making a game playable is a game made eligible to be voted for a Best of Show award. But they won’t let me cover it. I had to sign those rights away.

At 7PM or so, however, I started playing the game’s newly announced Horde multiplayer mode, and that I can cover.

Hit the jump to read how it felt to play the “Gears of War 2″ Horde mode:

The game has traditional multiplayer. It also has Horde. In Horde mode, a minimum of two — but a preferred five — players join together as a Cog squad. Players can choose to control any of the “Gears” lead characters. They can’t play as the Locust. The goal is to survive increasingly tougher waves of Locust enemies, with at least one player needing to survive a round in order for the game to continue.

A trooper armed with a flamethrower came in to burn our squad.

Horde mode gets tough quickly. At the party, I played on a five-player squad. I chose to play as Baird, a choice that seemed to only have cosmetic effects rather than any gameplay significance. We played on a level called River, which featured roadways on both sides of a mostly-drained river, a couple of houses, snowy trees, some crashed trucks and sandbags for cover. (I later saw another level that took place in a concrete courtyard where laser fences separated friend from foe; but those fences could be deactivated with the press of an in-level button.) At the start of the first wave on River, just a few Locust attacked, maybe five total, if that. Some enemies were foot soldiers. Others scrambled like insects.

Each subsequent wave produced a more terrifying assault of the Locust forces. Lumbering enemies with cannons drove me and my fellow players back. A trooper armed with a flamethrower came in to burn our squad. We took the flamethrower from him (a good weapon! A well-timed active-reload makes the flames temporarily shoot further). One new enemy type throws poison grenades and goes into a trance to revive his fallen allies. The Locust attacks were mostly relentless, though the unfinished game did show some artificial intelligence bugs. Some enemies stood still, ripe for the taking. Most did try to maul me.

Horde mode helped me try some of the game’s new features, all of them pretty violent.

Horde mode helped me try some of the game’s new features, all of them pretty violent. You have greater advantages over nearly-beaten enemies. Standing next to an enemy who is reduced to leaning on all fours lets the player press any face button to initiate either a quick kill or a scripted finishing move (a flurry of fists for a beatdown, a curb-stomp). When the tables are turned and you’re on all-fours, you can crawl away, hoping a teammate will revive you. You can only survive for a few seconds, before you can crawl no more and die. Another new features allows the player, while fit and fighting, to grab fallen enemies and use them as living shields. He or she can also set up a mortar-launcher in the ground and fire explosive projectiles up and down to the enemy. Slightly less violent than all this, the player can have his character grab a metal shield and then fire from the cover of the shield with (only) a pistol. The shield can be planted in the ground for extra cover.

In a half hour the players with whom I was tackling Horde reached Wave 7. By that time our luck ran out. We had begun to wind up half-terminated at the end of each round. One round ended with just one of us still standing, heroically facing down the Horde. (”Dead” players can fly a camera through the level, but I was told by an Epic developer that voice chat between those players and the “living” one will be cut off in the finished game, so as to make survival harder). Players earn points for kills — and even, in the final game, for any damage inflicted onan enemy another player then kills. But points didn’t help us with Wave 7. None of us survived.

Bleszinski said he hasn’t been able to survive past Wave 27.

By chatting with “Gears” originator Cliff Bleszinski I learned a little more about the Horde mode. The developers’ target is a 50-Wave story-free Horde mission-structure. Bleszinski said he hasn’t been able to survive past Wave 27. Sounds like Wave 50 will be a challenge. Given how long each later Wave can take, players will be able to bookmark their progress at every five waves.

I asked Bleszinski if the Horde idea harkened back to a specific old-school game. As I asked, I realized the answer he was going to give and one that I agree with: fighting waves of enemies is the battle plan for most old-school arcade games. Horde is a throwback — a good one.