Depending on your rank in each mission - which can be anything from a D to an SS - you can expect to new earn skills for each of the eight mercenaries. These include anything from restorative powers to improved weapon handling to increased critical hit rate. Each character can equip up to three perks, allowing plenty of options for strategy. There are 30 to unlock in total, but this is a slow process. Improving what would otherwise be a poor progression system are extra costumes and medals, which reward specific actions in combat with a nice shiny medal.
As with many games of this ilk, combos are the way to big scores. String together kills quick enough and you'll be awarded extra points. It concerned me how little I cared about my score, though. For a game that's all about racking up as many points as possible, it would have been nice to compare that number with friends. Mercenaries 3D is crying out for online leaderboards in some form, but sadly they are myseriously absent. Without such a feature, it's incredibly difficult to muster any drive to replay levels over and over again - which is really the thrust of the whole package.
There is both local and online co-op, however, which boasts a solid netcode and no signs of lag. In this 'duo' mode, both players contribute towards the combo, resulting in much higher scores than singleplayer. That said, there's obviously no support for voice-chat on the 3DS, so conveying a strategy plan to your partner is hard work.
The game is graphically accomplished but the frequent animation problems stick out like a sore, mangled thumb. Distant enemies are missing frames of animation, resulting in a horrible jerky motion. What's worse, you can literally see the moment where the animations are swapped - the exact point when an enemy crosses the threshold and they gain a few more frames.
The fast-paced, score-orientated nature of Mercenaries mode remains intact for the 3DS version, but even with all its bells, whistles and 'duo' co-op play, it never feels like a 'proper' game. There is a demo for Resident Evil: Revelations on the cartridge, which is indeed a 'proper game', but as this is over in a minute or two, it's doesn't offer much of an incentive.
If you're not entirely sure whether you're going to enjoy The Mercenaries 3D or not, ask yourself this: is £35 too much to spend on a mini-game ripped out of Resident Evil 4?