At the launch of the PS Vita last year, Tecmo Koei presented Ninja Gaiden Sigma Plus, a port of an early PS3 game that was also a port of an original Xbox game. The port was solid in the graphics department, and it was still fun. With the Vita nearing its first birthday, Tecmo Koei brought Ninja Gaiden Sigma 2 Plus, which can't be considered the definitive version of the game. Due to some technical snafus, it will probably go down as the worst version of Tomonobu Itagaki's final game as head of Team Ninja.

The game is set one year after the events of the original Ninja Gaiden for the NES. The CIA has come to Tokyo to find Ryu Hayabusa and warn him of an impending threat to his village and the world. Agent Sonia is briefly kidnapped but rescued by Ryu, who learns that his village is under attack by the rival Spider Ninja Clan. Upon arriving home, he learns that the leader of the clan is going to use the village's guarded Demon Statue to resurrect the Archfiend. It falls on Ryu to stop them from summoning this evil force.

The story works, but you have to accept some of the quirks of Japanese storytelling. There are lots of dramatic pauses in the dialogue, and there's a good amount of posturing by the main players. The villains often spout dialogue that seems hammy, and the twists are very predictable. While it isn't exactly the most memorable of plots, it's enough to drive the action without seeming too silly or preachy.

Action is the real reason why players will come back to the game, and fans of the first Vita game know what to expect. By nature, the game is a hack-and-slash title with a focus on combat. Though you have your fair share of pits, wall runs, and wall jumps to traverse the environments, you'll spend most of your time fighting hordes of enemies. Your arsenal consists of standard quick and heavy hits alongside an infinite supply of shurikens and arrows for ranged attacks, but you'll be doing this with different weapons. Each weapon gives you the power to unleash different combo types, including the ability to juggle enemies in the air to finish them off with an Izuna Drop or pull off a finishing move that severs them limb from limb.

Despite the hack-and-slash nature of the game, there's an emphasis on the strategic use of defense and unleashing spectacular combos. Most foes try to hit you with combos, and some even use counter-attacks and big finishing moves to counter the button-mashers. This occurs periodically on the lowest difficulty levels and very often on the higher ones, so the game is trying to discipline you into learning how to block and attack smartly and efficiently.

Sigma 2 Plus has quite a few modes in store for the player. The story mode is the same as the home console versions, with a double-digit completion time for those who go through the story at least once. The brutal difficulty of the original incarnation is still there for those who really want to challenge themselves, but there's an easier difficulty level available, too. Enemies still require you to learn their patterns, but blocking and dodging are automatic when you're low on health, and the enemy count isn't as high. Beyond that, there's nothing really different in the story mode this time around, so if you've played it on the PS3, you don't have much of a reason to go through it again unless you want to play it while you're on the move.

Prologue isn't so much a mode as it is a motion comic. The 10-minute comic features the final fight between one of the vampire lords versus both Ryu Hayabusa and his father Joe. The conclusion provides a good segue into the main story mode, and while it isn't completely necessary, it's fun to watch for those who are interested in the lore behind the game.

Chapter Challenge tasks you with playing through the game's previous chapters, this time with a scoring system that is determined by the items you pick up and your combos and kills. The idea is sound, but a few things that make it seem odd. For one thing, you never get a real score for the level until you complete it, and considering how long the levels are, each stage requires more of a time commitment than what's expected for a portable game. The length of each stage is also impacted by the fact that everything from the story mode shows up intact, including cut scenes and hints. The presence of save shrines ensures that you can complete each stage at your leisure, for the most part, this is merely a forced playthrough of the story mode but with the addition of a score.

Tag Missions chunks the game's levels into smaller arenas so you can fight a few waves of enemies at a time, this time with a friend in tow. You can control Ryu as well as fellow heroes Ayane, Momiji and Rachel, each with his or her own weapon sets and costumes — including some Vita-exclusive ones for the ladies. As in the console version, you'll work alongside your partner to take out the enemy waves. However, your partner is completely AI-controlled except for the few times you switch over and control them directly. There's no online or local play, and even though the game isn't exactly clamoring for multiple players, it's puzzling to see it omitted from a console that's completely online-capable. The AI does a decent job taking care of enemies, and though it doesn't die too often, you'll still take on all of the enemy forces yourself, making this more of a survival mode than a real "tag" mode. At the very least, it doesn't make the same mistake as Chapter Challenge in that it really feels like a sub-mode to the game instead of a retread of the story.

Finally, there's Ninja Race, a new mode for the series. You'll go through previously completed chapters of story mode, this time with a time limit that you must beat. Each level is split into sections. Enemies slow you down, and while it would usually be advisable to avoid them, beating them provides some time and speed bonuses, so you must try to figure out the right balance between running and fighting. You can play as all of the characters in Tag mode, making the missions feel a little bit different. However, with it retreading the exact ground as the other modes, there's not much of a reason to bother with it aside from gaining the trophy.

If there's one negative about the gameplay modes, it's the camera, which can sometimes act like another enemy. Just like the first game, Sigma 2 Plus has a moving camera with fixed angles that is supposed to replicate cinematic battles at every opportunity. The problem is that the camera often picks the wrong angles during fights, masking enemy movement and location until it's too late. There are also a few times when the camera is caught behind objects and obscures some of the action. Unlike most games like this, the camera isn't a free-roaming one, so while you can shift it left or right, you can't position it to get a better angle, and any shifts you make are temporary since the camera snaps back to the default position. You'll learn to deal with it, but I wish the team would've improved on this feature.

As far as the controls are concerned, the game has seen some improvement over the original. There's less emphasis on the use of Vita-specific features for some actions. You still have the touch-screen if you want to draw your bow, but the rest of the game relies more on traditional buttons and analog sticks instead of the gyroscope and rear touchpad. On that note, the game feels responsive to both movement and action. About the only thing that is sluggish is the default camera movement, specifically when you have your bow drawn. Thankfully, a few options tweaks fix the problem, making the game's controls near-perfect.

For the most part, the graphics are good. The environments are very detailed and rich in color, something that really benefited from the game first being developed for a current-generation console. The character models also sport some good detail, and the animations are smooth, nicely matching the quick movements of the attacks. The particle effects are similarly nice, but there's lots of gore accompanying the kills — something that was sorely missed in the PS3 version. Limbs are severed from bodies, heads fly off with just the right swipe, and all of this is punctuated by a decent amount of blood spray. The cinematics are pre-rendered instead of made with the game engine, and while it isn't seamless, the difference in quality isn't as pronounced as expected.

Where the game falters in terms of visuals is in the resolution and the frame rate. It wouldn't be fair to expect Xbox 360/PS3-caliber graphics from Sony's handheld, but few would have expected to see resolution changes occur on the fly. One moment, you'll see the game presented wonderfully on the system's OLED screen, and the next moment, you'll see the game reach PSone resolution with lots of aliasing and blocky characters. Playing at a consistent frame rate also plagues the title. Just like the first Ninja Gaiden title for the Vita, the game caps out at 30 frames per second, which isn't the target 60 fps on the home consoles, but it is decent enough. It never really holds on to this frame rate cap, and while those playing at the default difficulty level or lower won't notice the inconsistency, those playing at much tougher difficulty levels will notice that the game stutters far too often. This makes playing at higher difficulty levels much more difficult than expected since your timing differs greatly per combo, leaving you open to punishing counter-attacks. You can mess around with the options to alleviate the particle effects, characters and blood that slow down the game, but that ruins the console's plug-and-play nature. These frame rate issues never plagued the first game, so it makes you wonder what went wrong.

Those who have played with the console versions of the game will find that the audio is relatively unchanged. The effects are fine, and the music provides a nice modern movie mix that does well to amplify the emphasis on fast and frequent action. The voice work isn't terrible, but it isn't high-caliber material, either. Like the previous Vita version, the game only comes with an English vocal track, so the home console versions would certainly be the way to go for those wanting the original Japanese vocals.

At its core, Ninja Gaiden Sigma 2 Plus isn't a bad action game. The action is still very combo-heavy and less tolerant of simple button-mashing tactics. The story is decent enough for those who can tolerate the typical plots of action-heavy anime, and there is a decent amount of gameplay to be had. The constant decrease in the resolution and the frame rate is disheartening, and the camera issues can be frustrating. There's no real reason for those who have played the game on the PS3 or Xbox 360 to consider this port, especially since nothing of significance was added in this iteration. For Vita owners, this isn't a bad title, but it's only recommended if you've already gone through the first game and experienced the polish there. You also shouldn't play the game on anything above the normal difficulty level — consider yourself warned!

Score: 6.5/10