I'm not fond of developer swaps in the slightest. When a successful game comes about, most of the time it reached that height of popularity due to the hard work of the team behind it, so handing over the reigns to a different development teams for whatever reason is almost always a scary situation. Sometimes it works out for the best, such as Tomb Raider: Legend, and sometimes it doesn't - Splinter Cell is a perfect example of a series that constantly flip flops with mixed results. When Call of Duty 2 was a massive hit on the 360 and Activision announced that Call of Duty 3 would be helmed by Treyarch, the guys behind the Spider-Man titles and other CoD ports, I was concerned - especially when news broke that the game wouldn't even reach PC gamers, where the franchise was born. Now, a few years later, I see why it was done... because Infinity Ward were busy crafting what would be the biggest and most drastically different entry into the series yet - Call of Duty 4: Modern Warfare. Don't worry though, because Modern Warfare is still full of the same Call of Duty fun... and unfortunately the same Call of Duty problems.

CoD4 is full of highs and lows, to the point that I found myself constantly changing my overall opinion of the game. At times, such as during the stellar opening sequence where you and a squad of British soldiers infiltrate a cargo ship during a storm under the cover of darkness, the game is so theatrical that you can't help but have a great time. You watch your teammates use superb tactics to silently storm the ship and take enemies out with precision, before making a daring leap from the ship during a breach. Then the game grounds itself as you progress from mission to mission, just like any other Call of Duty. There are no squad controls and no new gameplay elements outside of weapons - and the theatrics slow down just a little.

Since the series is now set in modern times, it uses a fictional storyline to set the scene for a new war. A Russian ultra-nationalist by the name of Zakhaev is dead set on returning his country to the times of the Soviet Union, to the point where he revolts against the current government and takes control of a nuclear weapons stockpile. With rogue military forces giving him aid, Zakhaev sets up a coup in the Middle East to draw attention away from his own country, giving us two settings for the game. On the one hand you play through the eyes of "Soup" MacTavish, a British soldier in the 22nd SAS Regiment. Soup's missions sprawl across Russia where you're accompanied by the hilarious British forces, lead by Captain Price (who CoD vets will recognize). This is definitely the first area of praise for the game for me; the dialogue is not only superbly written, but incredibly well acted too. These guys really bring you into the battle with intense battle cries, as well as making you laugh your ass off with dry British wit and sarcasm.

On the other hand you also play as American soldier Paul Jackson invading the Middle East and working with the Brits to take out Zakhaev and settle the coup. As you can imagine, these levels are more in your face. When you first start off playing CoD4 you can easily see it being compared to the previous games, swapping between countries and characters before the inevitable conclusion - but luckily this game realizes that it has full control of the story and the characters and runs with it. For the first time CoD has epic plot twists, flashback levels that actually give some character development, huge moments of catastrophe and theatrics that put the rest of the series to shame. Nuclear blasts hit while you're riding in a helicopter, buildings fall down right in front of you, soldiers play the hero in grand fashion and die in even grander ways. The best part of the game is easily the storyline; you'll feel like you're playing an epic Steven Spielberg production instead of a WWII documentary.

In one particular section of the game you jump to the past and take control of a character previously only seen as a non-playable soldier during a two-man stealth mission. For the first time the series slows down in pace and becomes about recon, sneaking through the grass unnoticed as you make your way through a completely abandoned city that now resembles a ghost town, full of moody music and atmosphere. The section breathes life into this character and gives you a lot a respect for him when you see him again later. The series uses these devices to great effect in this modern setting and it's a great thing to experience. Unfortunately however, that's about all it takes advantage of. Whilst the gameplay introduces new modern weapons and tools, such as grenade launchers, night-vision and flash grenades, the gameplay engine itself remains very familiar. Actions such as rappelling down a wall are all automatic, whereas in a similar game like Rainbow Six: Vegas (albeit more tactical of a game than the arcade style CoD) you have full control of not just how you move and act while on the rappel, but you can also command your squad, something you only get to watch happen in CoD. Sure, you might not be playing as a captain or anything, but at times you feel a bit left out as you watch your team give orders to each other and pull off strategically timed assaults while you sit in the background.

Furthermore, the AI in CoD4 hits an astonishing low later on in the game; just when the campaign seems to have run out of theatrical situations and scripts, you're left defending areas for a set amount of time against wave after wave of forces that never end, no matter how many you take out. Whenever I died because I felt the game simply cheated me instead of outplayed me, I become a little irked - and I definitely remember being a little irked more than I would have liked. Even when you don't end up dying, it just isn't that much fun to shoot enemies who do nothing but run at you in the same pattern until a countdown reaches zero. Never did I watch an enemy and note being impressed by his tactics or maneuvers; even when they don't infinitely respawn, they all either sit and fire at you and take cover to reload, or run in a pattern until you fire at them, followed by them stopping in their tracks and returning fire. You don't have to worry about an enemy noting your position and then flanking you - but you do need to worry about being a huge magnet for grenades. I noticed that on the higher difficulties (which, in traditional CoD fashion, means the enemies are just incredibly accurate), an enemy could throw a grenade while looking in a completely different direction from where I was and it would leave his hand and fly right at me. Say for instance he is looking to your left, at a group of fellow teammates, he'd pull back to seemingly throw it at them, only to have it leave his hand and instantly fly to his left and land right on you.

On the more challenging levels, CoD4 often gives you the feeling that you simply shouldn't try to break the linear script that has been written and the best thing to do is just take down the enemies in the most obvious way, because most of the time whatever plan you're cooking up just won't work. Rockets going through helicopters, an impossible amount of grenades landing right at your foot - you name it, CoD4 seems to throw it at you if you go somewhere it doesn't want you to. There are of course exceptions, such as planting C4 on the ground where you know a convoy of trucks is about to pull up - that works fine and it is hilarious! On the easiest difficulty foes pretty much can't hit anything at all, which is nice for casual players, while the normal setting strikes a nice balance.

Though the game sticks tightly to the linear script and path written, the developers have at least written a fun one. Outside of the frustrating levels of defense from endless enemies and tiring battles in narrow spaces, the game has crafted some truly memorable moments. You invade a TV station that a terrorist is purportedly broadcasting from, you attempt an assassination with a massive sniper rifle from miles away, you experience a nuclear blast while in the back of a helicopter, you rush to the aid of downed soldiers as they're being surrounded by terrorists who want nothing more than to make your teammate a POW, and you even cut off the power to a whole building as you storm inside and watch enemies cower in the pitch darkness. There is even one scene in the game where you and a teammate take out a pursuing helicopter in grand fashion, only to have it come crashing down directly on top of your position. If it weren't for the dramatic and often brilliant storytelling of the gameplay, CoD4 would have been a big flop in my eyes - but the level design throughout most of the game is fun and exciting, always offering somewhere new to fight, or a different objective to accomplish. It dips down to horrible lows a couple of times, but this doesn't stop it from being pretty brilliant overall, so much so that it makes up for the lack of innovation where the gameplay itself is concerned.

Graphically, CoD4 takes full advantage of the next-gen hardware it was created for. The previously mentioned first mission, set aboard a cargo ship amidst a heavy storm, is one of the most visually satisfying scenes I've ever played through in a game before, with water crashing over the ship as it also pours down from above, flooding in once the ship breaches. Similarly, the epilogue of the game witnesses an airplane experiencing a breach mid-flight as everything is violently ripped from within it. The varied terrain, from the dry, heat-drenched Middle-Eastern setting to the damp fields of Russia's agriculture look drastically different, but damn near perfect if it weren't for the flat, pixel-ridden grass you see when laying down! Enemy animation could also use a lot of work, as many don't flow very well at all and instead look very automatic and forced, especially when they're running; however, the scripted death sequences and bodies falling from high areas are particularly well done. One of the most visually stunning sections of the game comes during the flashback sequence that takes place in Ukraine over an abandoned amusement park. This is one of the most eerie sequences I've played through and it doesn't fall back on ghosts or any 'jump' moments to be spooky - it's all in the graphics.

The sound is also excellent, though it hasn't changed a whole lot for the most part. The gun sounds have obviously been upgraded to match their modern counterparts, while the music is still as epic and orchestrated as ever, fitting most scenes to a tee. The real showcase of the sound, however, is the tremendous voice acting from everybody involved. Not only is it intense but it's actually very realistic; in one section you take control of a gun aboard a helicopter as you hear your commander shout out targets while communicating to other soldiers elsewhere. They relay information to each other back and forth, at times misunderstanding each other and having to elaborate on specific targets and locations. Not only is this well acted, but you know it's well-written when the voiceovers end up asking questions that you yourself would have asked at the same time!

A huge improvement over any other CoD game comes with the online multiplayer. Where this was little more than an afterthought in CoD2, but with some unique ideas, and a good attempt riddled with problems in CoD3, this time it's almost flawless. Using a party system borrowed from you know where, players can surf through various game types together or alone and it's all almost instantaneous. You don't sit waiting for people to join; you just hit search and you're playing. Furthermore, there are dozens and dozens of online challenges to unlock and complete, which in turn enable better equipment and attachments such as laser sights or new perks like dropping grenades when you die, or being able to pull out your pistol and go out fighting when you're killed, much like the enemies do in the single player.

The gameplay in multiplayer is a straight up fast-paced arcade romp. You select your class from the preset list, which includes Assault, Sniper, Heavy and so on (with more classes becoming available as you gain experience), or create your own by combining various weapons and the perks you've unlocked. Once in the battle, it's as hectic as ever; rockets are flying, C4 is planted all over the place and players are getting blasted from behind. And if you die? No worries, as you respawn almost instantly and you can watch a short clip of your enemy killing you as well! While that might not sound like fun, for those times that you simply can't believe you were killed first (or where you have no idea just who killed you) you'll learn to appreciate the KillCam.

Unfortunately the online mode doesn't include any vehicles to control. Whereas games like Battlefield let you drive Humvees or fly helicopters, CoD4 is a very traditional close-encounters game. The maps are fairly small and in your face, with numerous structures to climb through and small bridges to run across. They fit the style of the gameplay perfectly, but one extra twist is thrown into the mix; when playing well, your team is rewarded. If a player obtains three kills in a row without dying then he or she can activate a UAV radar that pinpoints enemy positions. As more and more kills are earned without a death, players can start calling in helicopters and even air-strikes to take out enemies and gain a boatload of experience at the same time. CoD4's experience system offers a lot of replay value for the online aspect; players are constantly unlocking new weapons, new challenges, upgrades and even game types to play online. Ironically there are no online achievements this time around, but with so much to unlock and so many ranks to achieve, it really doesn't take out the incentive to play. This is easily the most fully featured and progressive online mode to hit the 360 yet, especially with the ability to create your own class of player instead of selecting from the pre-made ones. Hell, there's even a classic mode where players all have the same gun and battle for weapons laying around on the map! The variety really is endless.

If you're going into Call of Duty 4: Modern Warfare expecting a game that feels like the previous entries but with a modern setting and modern guns then you'll have an absolute blast. If the words 'Modern Warfare' give you expectations along the lines of GRAW or Rainbow Six however, both of which are very tactical and realistic as well as theatrical, then you will be severely let down in terms of how the game plays. Either way though, everyone will love the storyline and movie-styled sequences of the campaign, making you a winner regardless of expectations - even if you're tired of the CoD game engine and questionable AI, the campaign offers moments of big budget quality that most games just don't have and they are worth experiencing despite how you feel about the gameplay itself. The online mode has plenty of life in it even when the single player is finished; just do yourself a favor and don't play on veteran unless you're doing it for the achievement, because it definitely will dampen the overall experience of the story and theatrics when you're dying for silly reasons constantly. Call of Duty 4 is a great leap in the right direction for videogame storytelling and in-game action sequences, but next time around I'd like to see some more gameplay innovations, particularly when other games have already made the advancements that CoD4 has so far failed to achieve.

Reviewed by Christopher Martin for AceGamez (All Rights Reserved).