On the violent plains of the Old West, arguments often ended with a Mexican stand-off. You remember how these work: a group of angry men stand around in a loose circle, guns twitching in their hand. Everybody twists their face into their hardest scowl, then the bullets start to fly. In most cases, pretty much everyone dies - perhaps leaving a lone survivor to rob the bleeding corpses.

In actual fact, I have no idea whether these violent confrontations really did take place. I'm no historian, and my only frame of reference for this era is the work of Sergio Leone, John Ford, and all the other big-name cowboy film-makers. In other words, I know the fantasy but not the reality. As luck would have it, that's not a problem - because Red Dead Redemption is a game that clearly loves all this iconography. Around here, Mexican stand-offs happen all the time. In fact, they take place at the start of each and every competitive multiplayer match. At the start of a round, all the players are arranged in a ring, facing each other. A brief on-screen prompt suggests a rival to take with you to the grave, but as soon as things kick off you're free to target anyone you like.

As years of cinema have trained us to expect, most stand-offs are resolved in a matter of seconds: everyone opens fire, and most of the participants are decimated in a heartbeat. If you're of a cowardly (read: sensible) persuasion, you can try running away like Mr Pink in Reservoir Dogs; doing this can enable you to pick off the rest of the survivors from a distance, but I suspect it'll also lead to you getting singled out for retribution at the start of the next round. At any rate, it's a bit of a wimpy tactic. You're supposed to be a hard-boiled high plains drifter, after all.

This initial stand-off ensures that every multiplayer match starts with an outburst of frenzied violence. As soon as the pack has been whittled down to a lone survivor, the match begins in earnest; at this point the pace and tone of the action changes considerably. Rockstar has shown off four competitive match-types so far, but in all of them there's a surprising emphasis on tact and stealth. It only takes two or three bullets to kill a man, perhaps just one if you score a headshot, and as a result you have to play very carefully if you want to stay alive for any length of time.

The first straight competitive match I tried at last week's demo was a straight-up free-for-all deathmatch in the Mexican market town of Chuparosa. Each player has an on-screen map of the surrounding area, but other gunslingers will only show up if they run or fire their weapons. As a result matches tend to carry long periods of tense quiet that are suddenly shattered by loud outbursts. There's an interesting risk-reward dynamic at play here. If you're moving slowly then you represent an easy target for anyone who might have you in their sights, but if you run everyone will see and hear you coming.

Weapon choice has a significant impact too. Shotguns are devastating at close range, but their slow rate of fire means you're largely shafted if you miss. Pistols offer a more flexible alternative, since they're still effective at medium range and allow for several shots in a row - but they're not that powerful. Personally, I found I had the most success with rifles, which seems to work best from a high vantage point. Almost all of Chuperosa's whitewashed buildings could be entered to gain access to the roof, while others like the battered church could only be climbed with a bit of exploratory clambering. Rifles remain fairly accurate even at long distance, particularly if you're using one with a grubby, dirt-flecked scope, and it's not uncommon to find yourself trading bullets with a foe on the other side of town - waiting for a distant head to rise out of cover. Of course, if you get too preoccupied with one enemy, there's every chance that someone else will flank you and put a hole in your unguarded back.

Fighters can carry one weapon in each of the main firearm classes at a time (including one scoped rifle and one regular variant), and alternative guns are stashed around the map in respawning crates. Green-tinged boxes allow you to replenish your Dead Eye - the bullet time-like system, triggered by clicking in the right stick, that is normally fuelled by successful kills. Unlike its single-player variant, there's no slow motion effect for multiplayer deadeye; instead you simply "paint" targets all over your chosen foe, then unleash them in an automatic burst by pulling the right trigger. As you'd expect Dead Eye can be highly effective if you have the drop on someone, but in head-on confrontations it's time-consuming and very risky. Headshots, by contrast, can be a real life saver (for you, rather than the person on the receiving end). If your opponent is locked on to you and is simply blasting away, it's possible to put them down with a single shot, before they can finish you off.

Ultimately, none of these tricks will be enough to save your sorry hide if you're fighting several people at once. In team deathmatch, or Gang Shootout as it's called here, you'll soon learn to appreciate the old maxim of "safety in numbers." A like-minded buddy can cover your back, help you to gun down a troublesome sniper, and just generally keep you alive for longer. As with the rest of Red Dead Redemption's multiplayer, it's quite easy to find yourself roleplaying in situations like these: you and your chum aren't just players 1 and 2, you're Butch Cassidy and The Sundance Kid, Pike Bishop and Dutch Engstrom, Dawn French and Jennifer Saunders. Okay, perhaps not that last pair - but you get the idea.

A similar degree of "instant storytelling" can be found in Goldrush and Hold Your Own, two game types that revolve around stolen bags of gleaming metallic goodness. The first mode is another free-for-all-setup where players fight over a limited number of sacks dotted around the map. Once you've grabbed one or two bags (taking two slows you down), you show up on everyone's radar as a giant flashing "KILL ME!" sign. Alright, it doesn't actually say that, but it may as well do; to score a point you need to lug your wares to one of several cash-in points, resulting in the perfect opportunity for an ambush. There's something particularly evil about waiting until someone is mere steps away from their goal, blowing their head off with a shotgun, and then stealing the gold for yourself. Mark my words, friendships will be lost over this kind of thing.

Hold Your Own is essentially good old Capture the Flag, with two teams battling to grab a single bag from each other's base. Unlike the other match types, these contests are played out on sprawling open maps - or at least, the one in the demo last week was. "Diez Coronas" is a large canyon-like area with two sprinkling of buildings at either end, and a large rock formation in the middle. The increased scale of this map allows plenty of scope for zipping about on horseback, and there's also a cannon that can be used to rain explosive death right into the "goal" area. From what I've played it's also a lot more slowburn, requiring sharp teamwork to make a successful raid. In the event of a draw, the game becomes a sudden-death battle for survival. If you're the last person alive on your side, this is pretty scary - particularly if you're playing against a Rockstar representative who knows the map like the back of their hand.

As I've said, it's quite hard not to find yourself playing make-believe during these matches, especially when the EUPHORA physics engine makes something awesome happen - like a player going limp as they take a headshot while sliding into cover. However, if you're really in the mood to play cowboy alongside a few chums, your best bet may be Free Roam - a mode that exists both as a playable lobby, and as a fully-fledged experience in its own right. Each of the "proper" competitive maps is actually a fenced off part of RDR's open world, but in Free Roam you'll have the whole thing to explore. Up to 16 of you can be walking (or riding the plains) at once, and up to eight of you can band together to form a posse. One player is automatically assigned to be the leader of the posse, and he or she can mark out rallying points on the map, resulting in the same kind of radar guidance that you'd get in a single-player mission. There will also be some way to warp around the map, which is handy as it would take ages to get there otherwise.

The first time you enter Free Roam, the immediate temptation is to find your mate and to decapitate him, his horse, or ideally both. Once you've finished messing around you'll find that there's a huge amount to do: challenges to take up, gang hideouts to raid, and plenty of random NPCs and wildlife to molest. Every action you take earns you XP, which in turn affects your default weapon loadout and horse. During my demo I was stuck riding a donkey that made a dreadful racket and bucked me off every time I tried to make him gallop for too long, and yet somehow I grew quite attached to the long-eared bugger. When he was unexpectedly decimated by a sudden TNT explosion, I was quite mortified... until he respawned a few moments later.

I get a sense with Red Dead Redemption that no matter how long I spend writing about it, there are always a hundred things that I've barely touched upon. This is a massive, massive game, and I suspect that messing around in Free Roam will be just one of the many highlights of what the full game has to offer. In some ways, the Western setting feels more suited to this kind of multiplayer hi-jinx, because rather than a dense city, there's loads of room to gallop about, to snipe at each other and to generally act like a homicidal fool in a Stetson. It's true to an extent that Red Dead Redemption will be a tougher sell as far as the public are concerned, simply due to the fact that gangsters will always be more popular than cowboys, but there's no doubt that this is going to match if not exceed the scale of GTA 4. We've had a generous swathe of heavyweight titles in 2010, but Red Dead Redemption has the potential to be one of the definitive gaming experiences of the year. May 21 can't come soon enough.

Red Dead Redemption will be released on PS3 and Xbox 360 on May 21st.