Space - the fragging frontier. N.O.V.A. 2 goes where its predecessor has gone before, yet it does so with more features, more weapons, tougher enemies, and greater overall polish.

While not all the changes this sequel brings are ideal, the attention to detail and high production values deserve applause.

A couple of questionable action sequences and a hard-to-believe story prevent the single-player campaign from being truly stellar, but there are few complaints to lodge against the robust multiplayer and ace presentation.

The fight continues

Intergalactic cowboy Kal Wardin is summoned once again to save humanity from an alien threat, this time packing new weapons and abilities.

Your goal through the course of the ten-mission campaign is to smash the mysterious Volterite race with the butt of a rifle or riddle them with bullets - either way, it's all about action in this non-stop thrill ride.

The plot lurches from mission to mission, but it serves as a vehicle for some truly spectacular action sequences. Branching beyond on-foot action and on-rails vehicle shootouts, N.O.V.A. 2 has you arranging turrets to defend a base against waves of enemies and piloting a towering mech through an alien weapons facility.

Running through a fortified Volterite base to hack terminals to free your virtual pal from a digital prison is tense and challenging. Taking out a mech on foot is an exhilarating test of skill. Levels are larger, too, with more interesting layouts and secret ammo caches that can only be found if you're constantly on the lookout.

Running and gunning

Amplifying the action in this way increases variety. However, it also has the effect of diluting combat. It's like a Michael Bay movie at times with gunfire and explosions everywhere.

For instance, you're frequently prompted to man a stationary turret and mow down enemies. While having that much firepower can be fun, it doesn't offer the same visceral challenge as sparring with Volterites using a rifle or shotgun.

It can be taken as a compliment or criticism depending on what you're looking to get out of the game, but either way it's a subtle shift from the first game.

Some of the variety, however, isn't fun. For example, in one early level you defend a temple from enemies using robotic turrets. It's an interesting concept, but not terribly enjoyable.

Camping out in the same small area for 15 minutes spraying aliens with gunfire just isn't compelling. These rare mediocre moments stand out only because the rest of the campaign is so entertaining.

See you online

Multiplayer is practically unrecognisable in comparison to the barebones original. It makes all the difference in terms of replay value with a sophisticated system of ranks and rewards that grant access to new weapons and equipment as you level up.

An evolution of concepts implemented in Modern Combat 2: Black Pegasus, multiplayer is slick, feature-rich, supports more players, and is just plain fun.

Classic modes Deathmatch, Team Deathmatch, and Capture-the-Flag are here, as well as Freeze Tag and Instagib, all playable on a whopping ten maps. It's a ton of content for online and local play. Gameloft has truly set the standard for multiplayer with N.O.V.A. 2 and for that alone you ought to play it.

For all the enjoyable moments in the campaign, multiplayer carries N.O.V.A. 2 to the finish line. Without question, it's the finest first-person shooter on iPhone and iPod touch to date, replacing its predecessor with sharper action, killer graphics, and the best multiplayer experience around.

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