The open world FPS is something we haven't really experienced yet. I guess the closest we've come is the MMO Planetside, but in the single-player space game designers definitely favour linearity over exploration. THQ's Frontlines looks to change this, with levels being larger and more open than those found in the competition. With an online component that has all the hallmarks of an Xbox LIVE classic, do Battlefield and Call of Duty finally have some strong competition in the crowded military FPS space?

Frontlines is very much a game of two halves, although the gameplay across each is commendably similar. The first is this supposedly open-world single-player campaign. Set in 2024 amidst much hostility and global war over oil shortages and the depleting supply of natural gas, two alliances are formed: the Western Coalition, consisting of the United States and the European Union, and the Red Star Alliance, formed by Russia and the People's Republic of China. You play as a solider fighting for the Western Alliance. Things open like any other FPS, with you pinned down and having to fight off a wave of enemy soldiers. What makes Frontlines different to your average FPS is how each level progresses. Essentially you have to capture control points placed around the map, moving your squad forward into a better position to take on the enemy.

It's very similar to what has recently become popular in large scale online shooters, except this time you're up against far more enemy soldiers than you would in multiplayer games. Capturing a control point simply requires you to stand firm in that area (handily marked by some coloured smoke) - something that's easier said than done given the ferocity of the enemy attacks. When you're not gaining ground you'll be taking out marked enemy vehicles, using control panels or planting explosives. In truth it's nothing you won't have already done countless times in other first-person shooters, but here you can go about things in a way that suits you.

On any given level you'll usually have a number of objectives, with each of these accessible in any order and from numerous directions. In frontlines you don't get the sense that you're being funnelled into a pen, with enemies waiting to ambush you, giving it a different feel compared to the likes of Call of Duty 4. If you want to take an enemy stronghold on from the front, so be it, but if you want to manoeuvre around the side, that might give you a better chance of success.

Threats will come from everywhere

Add to this the ability to use vehicles. For most of the levels vehicle use is optional, so if you want to use a tank you can hop in and take command, but if you want to try and take out the armoured enemy vehicles on foot, ideally with a homing missile or two, that's an option too. You'll also gain access to neat military gadgets, such as a remote control attack chopper, a mobile explosive device and a gun turret on wheels. These add another layer of depth and even more options to choose from. In fact, you could easily play through the entire campaign again and have a considerably different experience.

Even though you have plenty of options available to you, it is slightly disappointing that some of the more exciting vehicles don't come into play until over half way through the campaign. Helicopter usage is completely absent from the opening levels, and while the tanks are fun at first they soon become a little tiresome and slow. Fair enough, you have tones of other tools at your disposal, such as calling in an air strike, but some of the larger levels earlier on would have really benefited from an aerial attack that you're in command of.

Visually the size of the environments makes up for any roughness

What Frontlines manages to do really well is capture the feeling of war. At times you'll have enemies coming at you from all directions, rockets will be screaming through the air, tanks will be bombarding your position with heavy fire and your team mates will be laying down suppressive fire. As good as this is, Frontlines just doesn't have the spark and edge in its single-player campaign to make it truly special. Developer Kaos Studios has managed to take what is essentially a multiplayer game dynamic and turn it into a highly entertaining single-player game, but Frontlines misses out on the special moments you'll find in the more scripted shooters.

Rather than have jaw on the flaw moments play out in-game, in Frontlines they're relegated to cutscenes. If you accomplish something you want to see it happen in the game, not in a totally non-interactive video. Speaking of the videos, the story in Frontlines isn't quite as engaging as many of the most popular shooters on the market and despite things being told by cutscenes it feels like you're just jumping from one war zone to another, without any real sense of consequence.

If the single-player game suffers slightly because of its bold approach to gameplay, the multiplayer portion of Frontlines excels. It's a lazy comparison, but what you have here is a Battlefield-like multiplayer FPS, complete with ground and air vehicles, objectives and control points. Given that Battlefield Modern Combat is getting a little old in the tooth this is no bad thing, but the big point in Frontlines' favour is being able to play in mammoth matches of up to 50 players - although only on one map for the time being.

Whether or not you enjoy the massive-scale online battles will ultimately determine how fond you become of Frontlines, as it's by far the game's most impressive feature. Maps are truly colossal in size, absolutely requiring the use of the many vehicles, and the large player numbers means team work is essential. If you enjoyed the Xbox 360 multiplayer demo then you'll no doubt go crazy for the full game, which offers far more content and the larger maps that make for online games unlike anything you'll have played before on a console.

Using the many drones is great fun

Built on the Unreal Engine 3 Frontlines is no slouch visually, but it's not quite as polished as Epic's now legendary Gears of War. In its defence, Frontlines offers levels that dwarf those seen in Gears and there's far more going on here. Compared to its open-world FPS rivals it's by far the best looking, even outdoing id Software's recent Enemy Quake Wars. Things do get a little too hectic at points, causing some noticeable slowdown, but the game moves at a pretty slow pace anyway, making these moments unfortunate but far from a disaster.

Frontlines as a single-player game actually came as quite a surprise. I'd expected its open nature to feel like a series of watered down multiplayer matches, but once you get into the heat of action it's a thrilling experience. It's the multiplayer that will give Frontlines legs though, providing gamers with epic 50-player battles that really give the big boys of the genre a real run for their money. THQ hasn't had the greatest showing on next-gen consoles so far, but Frontlines has the potential to be a very successful franchise.