Okay, so you've probably gotten the message by now. I've written three previews for this game over the past nine months, and with hindsight I realise that they've all been making the same three points: a) ArmA II is awfully pretty, b) ArmA II is absolutely massive and c) ArmA II is cruelly realistic.

All these observations remain well and true, but I won't spend too much time making them for a fourth time. What I will say is that these are likely to be the first three observations that you yourself will make, should you take the plunge and buy this game. "Ooh, isn't it pretty?" you'll cry as you explore the island of Chernarus for the first time. "Wow, isn't it huge!" you exclaim, as you realise the full extent of your virtual playground. "Bloody hell!" you'll scream, as an unseen enemy fires a bullet into your digital skull, prematurely ending your game.

In simple terms, ArmA II is the world's greatest set of toy soldiers - an ultra-comprehensive military sim, playable from first or third-person perspectives, that lets you play around with everything from a T-72 tank to a MV-22 Vertical Take-Off and Landing jet. There are sniper rifles, Stinger missiles, laser target designators... there are even bicycles, for pity's sake (although your soldiers seem to ride them with an incredible sense of balance; you can grind to a halt and they'll remain bolt upright). The game is packed with literally hundreds of vehicles, tools and weapons - all of them painstakingly modeled on their real-life counterparts. The main question, initially, is how exactly you'll choose to play with them.

There's a campaign mode, naturally - we'll look at this in a moment - but there are also a spread of other options. There's a boot camp to help you learn the game's many features and controls; there's also a ready-made set of seven missions that allow you to jump straight into the action without the distraction of an on-going plot. There's also something called the Armory - an interactive library that provides a simple way to check out every model in the game. If you're feeling lazy you can just sit back and watch a video of your chosen weapon/vehicle/character in action, but a more fun option is to take the item in question out for a spin. You'll be free to mess around to your heart's content without the fear of someone attacking you, and at short intervals you'll be offered mini-challenges to try; you might have to reach a certain point on the map, take down a certain number of targets or race against the AI. Completing these mini-tasks will unlock new models, including all the wildlife that roams the 225 square km of Chernarus. So far I've evaded poachers as a stealthy hen and helped to guide a photorealistic sheep around a makeshift obstacle course. Fun times!

As enjoyable as the single missions and Armory are, the meat of ArmA II lies with the campaign and with the world of community gaming that follows. Or to put it another way, after completing the main story you'll be a battle-hardened commander, ready to take on whatever the internet can throw at you. As with the previous ArmA (and, indeed, Operation Flashpoint before it), this is a game that has been built with an online following in mind. Not only can you can play through the whole of the campaign with the help of three friends, but in multiplayer you can have up to 50 participants fighting over the entire map - each of them controlling their own battalions of troops and vehicles. On top of that, there's an extremely powerful set of editing tools for building your own missions. Considering that people are still making stuff for the original Op Flash some eight years after its initial release, you can expect to see plenty of new user-generated content in both the near and distant future.

Visually it can look near photo realistic

Before you start to delve into all that good stuff, you'll probably spend most of your time with Red Harvest - ArmA II's main campaign. Bohemia Interactive Studios has admitted that this was one area that was sorely lacking in their last game, and as a result it's clear that the Czech developer has put a lot of effort into making amends this time around. Red Harvest has around 12 missions for you to work through, and by the time you reach the story's bloody end you'll be trained in most - but not all - of the combat arts that the game has to offer (HALO insertions are mysteriously absent from the campaign, despite their presence in the training missions. I guess that's something for the community coders to play with).

Now, 12 missions may not sound like much, but what you've got to bear in mind is that each of these assignments can and will last several hours on one play through. The first two or three outings are relatively straightforward, providing you with a chance to get acquainted with the fiercely harsh realities of infantry combat. You'll also get to grips with the four controllable members of Razor Team, the gutsy recon unit you follow throughout Red Harvest. Your team consists of one grenadier/translator, one sniper, a heavy weapons expert and a medic, giving you access to a wide range of talents. You can switch any of the four scouts as you wish, though only Cooper the grenadier can issue commands to the others.

Get together with friends and you could play this for years

If you've played previous BIS games then you'll be immediately at home with ArmA II's action, but if you're new to this style game then you'll probably feel a bit intimidated by how complex and unforgiving it can be. One minute you're making decent progress through an occupied village; the next you're on your belly screaming as the screen warps and distorts in pain. Thankfully your mates may be able to save you if your enemies fail to kill you outright with an attack, and you'll certainly find yourself returning the favour - dragging your buddies into cover so that you can administer some life-saving first aid. Even on the easiest setting, you may be surprised by the speed with which things can fall apart, although the game helpfully gives you the option of highlighting allied and enemy troops - a useful setting, since you'll rarely have time to spot your enemy if you come under unexpected fire. On the flip-side, you can also turn off almost all the guides and help systems in the game, making for a truly hardcore experience.

After you've progressed a few missions into the game, things start to open up. It's at this point that the game gets really interesting, since you're essentially given free reign to do what you want. As a general rule, the game tends to give you a very broad goal or set of objectives before abandoning you to your own devices. This freedom is quite breath-taking when it first arises, but it's also rather scary. One early mission, for example, tasks you with finding a pair of communist warlords who've gone on the run. You're given a few places to start looking, but in a nutshell they could be anywhere on the map - all 225 square clicks of it. You can call in a helicopter to ferry you around the map, and you can commandeer pretty much any vehicle you find, but it's a bit of a head-spinner all the same - particularly as the game is fairly reticent about giving you concrete pointers. If you interrogate the locals you might get a decent tip-off, but there's no definitive answer as to where your target might be. It's the antithesis of a linear experience like CoD 4, and as a result you'll need a hell of a lot of patience and dedication to beat the level.

Things get even more complicated later on, and before long you'll find yourself roaming the map with a list of 10 objectives to meet as you see fit. Later still you'll find yourself dealing with RTS-style elements, commissioning new units and building an entire base from scratch. It's a wet dream for armchair generals, especially when you factor in how amazing all the vehicles and the landscape looks. Unfortunately, however, all this complexity comes at a price: the last ArmA was widely criticized for the number of bugs it contained, and while this sequel isn't as bad it still has quite a few problems. The game's initial release in Germany (via publisher Morphicon) was met with a raft of complaints from users, ranging from complete crashes to mission triggers that failed to, well, trigger. This 505 release seems far more stable, but I still suffered a few bugs - particularly when one of my guys got injured and someone else had to take command. At one point Cooper was left bleeding and screaming in a jeep; no-one would come to help him, and I was somehow unable to switch to O'Hara (my medic) to do the healing myself.

Normally these issues wouldn't be too bad, but unfortunately BIS has elected to give the player only as single save slot. While this undoubtedly creates a certain degree of tension, since in-mission choices have a greater degree of consequence, it also means that a bad bug could screw an entire level, forcing you to restart from scratch and losing several hours work. My other main complaint concerns the behaviour of AI controlled characters. While your team-mates and adversaries are amazingly competent when moving about on foot - flanking, taking cover and generally looking after their digital selves - they tend to be less effective in vehicles. I found my personal chopper-chauffeur to be a particularly bad offender in this regard. Sometimes he'd "pick me up" by hovering some 20 feet above my head, forcing me to run away to another spot before re-requesting the lift. At other times he'd insist on landing on the roofs of houses, forcing my squad to break their legs as they disembarked. On one occasion, I foolishly saved the game moments before he was due to land - only to find that he insisted on lowering the 'copter onto a lethal set of power lines. If we hadn't all died in the crash, I'd have killed the bugger myself.

For what it's worth, Red Harvest boasts a fairly decent plot that approaches war in an intelligent manner while still finding room for plenty of explosive hijinx. The game certainly doesn't shirk away from the darkness or moral ambiguity of armed conflict, and while the plot branches in a few key areas there isn't really a good or bad path to take - you make your decisions based on your instincts, and then later on you deal with the consequences. The subtitled Russian dialogue is an excellent touch but the English voice acting is somewhat patchy, and this along with the rather wooden "acting" of the human characters unfortunately detracts from the impact of certain scenes. Elsewhere the game serves up a decent array of thumping rock tunes and sombre orchestral pieces that nicely complement the mood of the game, while the sound effects for weapons and vehicles are largely very impressive. You can actually hear when someone's taking potshots at you, and trust me when I say that it's damned scary.

This is about as authentic as you'll want

Make no mistake, ArmA II is most certainly a hardcore title. Aside from the technical issues I've mentioned, its biggest problem is simply its own nature: it's massively in-depth, and that will always be off-putting to some people. Could BIS have made it more accessible? Perhaps, but at the same time I'd much rather have an ambitious game like this, even with its obvious flaws, than a simpler experience that dumbs down to its audience. Later this year we'll be inspecting Codemasters' own Operation Flashpoint: Dragon Rising, and while I have little doubt that it will be a more user-friendly product, I highly doubt that it'll offer the same degree of heart-stopping scale. This is the kind of experience that makes PC gamers proud of their machines, and I simply don't think it could work on another platform - although obviously I'd love someone to prove me wrong.

In an age where most developers are reaching out to embrace casual gamers, ArmA II is something of a refreshing exception. It is unashamedly ambitious in its design and execution, embracing rich complexity at the expense of accessibility. It is a game that makes you work for your fun, and that asks you to overlook a good deal of awkwardness, as well as a fair few technical hiccups - though I am sure that these will be sorted with future patches. If, however, you have the perseverance to stick with the game through thick and thin, to learn its ropes and to immerse yourself in all it has to offer, then ArmA II will last you for years.