Resident Evil: The Mercenaries 3D review As a series so intrinsically linked to experiments gone wrong, it's good to see that this re-working of Resident Evil 4's formula has turned out to be such a success.
Mercenaries takes place over a small number of maps taken from Resident Evil 4 and 5, without the merest sniff of a cutscene in there to string it all together.
The numbered stages focus on that all-important points total, which is jotted up from the number (and type) of enemies you dispose of, how quickly you manage to do it, and how many combo kills you can string together.
Early tutorial stages explain the simpler stuff as well as the key differences between this game and the source material, and there are more here than you might be expecting.
A stab at the bottom screen lets you switch weapons, Health replenishment is now a button press away and, as with reloading your weapon, this can be done on the move, albeit at a slower pace than normal.
These alterations contribute to a much faster and more frenzied style of play. Drawing your gun is the same - hold a button to draw your weapon, aim and fire - but clamp your finger over the L button and you're able to slowly move in any direction with the Circle Pad while firing.
This addition seems designed to encourage you to move in for melee attacks as time bonuses awarded for close-quarter kills are vital. A shot to the leg with one of the weaker weapons will allow you to walk up to them and deal a more physical brand of justice, and reaping time bonuses this way soon becomes routine.
That some of these moves are also unintentionally hilarious makes them even better. Brutes like HUNK and Krauser tend to whip out a big knife and shove it right into a downed ne'er-do-well's gullet, but feeble Rebecca produces a dainty little can of pepper spray. And Barry's own brand of justice is a slapstick headbutt, brilliantly named the 'Barry sandwich'.
Characters aren't the only unlockables. There are 30 different player upgrades to unearth, including weapon upgrades, health or stamina help, and melee or score boosters.
The biggest and best new feature is co-op. The same option in Resi 5 was ruined by a clunky weapon and item exchange system, but in Mercenaries it has been executed with the absolute minimum fuss.
Health supplements can be shared between partners just by standing next to each other, and playing co-op alongside a chum locally ensures that gunning down waves of shambling former homo sapiens has never been more satisfying.
With two of you united against the odds, there's a heightened sense of drama. Picking off nasties as they rush up on your partner's blindside makes every game feel like its own self-contained action flick.
Mercenaries presents a big challenge if you're the type to unlock everything a game has to offer, but where it disappoints is in the variety and number of stages.
There are effectively only eight different maps, although most have 'night' variants which are cosmetically different. Of course, as you work up through the rankings, the type and number of enemies change within each stage, but you're still effectively playing through recycled content over and over.
While it lasts, Mercenaries is the best pure action game on the 3DS, and the in-game visuals and sound are among the best we've seen on the console.