Red Orchestra has achieved a level of immersion previously only possible in singleplayer games.
For now, you and your team seem to be holding the enemy at bay, but it'll take more to keep them from advancing further. Your platoon commander calls in artillery on the enemy ridgeline, bringing down volleys of thundering shells that shake the ground beneath you. You continue tofire off bursts at the silhouettes until enemy fire begins to hone in on your position, causing you to duck down. Nearby, a friendly slumps down to their side, writhing in pain on the ground, struck by incoming fire. You dash to the tree he is at, leaning around and spraying at the enemy. It's clear that the artillery isn't enough as the Germans get closer and closer to your lines. As they approach, grenades are hurled in both directions. Your grenade hits its mark, and an enemy is knocked over, their leg blown off at the knee. The soldier next to you fixes their bayonet in anticipation for close combat.
Finally, the Germans make it into the trenches. You pull the pin on your last grenade, and release the spoon to let it cook. A second later, you toss it into a trench, causing another enemy to meet a grisly fate. As you dive into the trench, a German jumps in from the opposite side. Firing your weapon from your hip, your rounds miss their target and your weapon clicks empty. In desperation, you hold your rifle up and swing at the man standing before you. Miraculously, it makes contact, sounding a loud *CRACK* and knocking him to the ground. There are simply too many of them, and the message comes that the enemy has taken their first objective, an anti-tank gun position.
The combined sounds of artillery, grenades, and small arms are nearly defeaning as you fall back to the command bunker. After resupplying from the weapons cache there, you lean around a bend in the trench, ready to defend against the waiting onslaught. Grenades again start flying overhead, and your platoon commander adjusts artillery to come in closer. Again your position begins to become overrun, and you fall back to cover inside the bunker itself. A grenade flies in and you hit the deck, protected from the blast and shrapnel by your cover, but another soldier is not so fortunate. Enemies begin pouring inside from the trenches. Spraying wildly, you take a couple down, but as you turn to your left, a German charges wildly at you with a fixed bayonet, and sticks you in the gut before you can fire. The enemy has taken the command bunker. All that there is left to hold is a broken, ruined train station, which the enemy is now calling artillery down on using your own radio. Can your team hold out?
Welcome to the eastern front.
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The first thing to note about Red Orchestra is that you're dealing with a much more realistic game than most of what's out there, particularly in the multiplayer arena. Weapons have realistic ballistic trajectories, and it rarely takes more than one or two shots to kill someone with any weapon. Movement speed is vastly slower than games like DOD. Jumping is only of limited height and usefulness. There is a "free-aim" system that makes it even more difficult to aim when not sighted. But the real greatness comes out in the details. The fact that you can lean any weapon against any bump, stump, sandbag, wall, pillar, ANYTHING in such a simply and dynamic way is absolutely invaluable. Any weapon can be used for butt-strikes (and some weapons can also be mounted with a bayonet), unlike other games where, for whatever reason, none can or only select weapons can. MG barrels can overheat, and German MGs can have their barrel replaced (while the Russian one realistically can't be).
The gameplay itself is the most intense I've ever seen in multiplayer. Most important to this is how they've managed to really create a "front line" sort of feel, where there's a main line of resistance over which the action takes place (typically around an objective), as opposed to most other games I've played where everyone simply runs around all over the place. The result is that firefights are realistic and prolonged, as you pop in and out of cover (how many games have you played where cover is actually important?), taking both aimed shots and laying down suppressive fire. I've found that people seem to naturally work as part of a team, clearing buildings together, providing covering fire while others move up to assault a position, etc.
Likely the weakest point of RO is the tank gameplay, which while an improvement over contemporaries such as BF, does not typically mesh well with infantry play. The most important of the improvements here is in ballistics. Tanks have realistic levels of armor over their body (and corresponding weak spots), and cannons have appropriate power and penetration values. Additionally, rounds can simply bounce off (causing no damage at all) depending on the power of the round and the strength/slope of the armor. Furthermore, most tanks have both armor-piercing and high-explosive rounds, which each have advantages in different situations. Most importantly, there are separate driver and gunner positions, which makes tank gameplay slower paced and puts a great emphasis on teamwork when you act as part of a crew (they're also made it very easy for the gunner to communicate movements to the driver through use of the numpad). However, tank-based maps leave essentially no place for infantry, and tanks can be a dominating force on infantry-based maps (which, while perhaps realistic, can be quite annoying).
Graphically, the game is slightly dated compared to games like DOD:S or BF2, but the skins/textures and animations create a fantastic level of grittiness. The explosion effects are appropriately smokey and dusty. Death animations/ragdolls look extremely realistic. Bodies hit by grenades become bloody and often lose limbs. The real star on the media front, however, is the sound. There isn't really a way to appropriately describe it, but suffice to say, the sounds are powerful and intense.
For $25 off Steam, you can't really go wrong if this is the type of game you're looking for. If you want a more arcadey, run-and-gun type game like DOD or BF2, then you may not enjoy it. However, if you're looking for a slower-paced, more realistic, and more immersive multiplayer game, get this. Give it a chance and let it grow on you. The only multiplayer game I've seen that's as good as this is World War II Online, and this doesn't require a $15/month fee.