The best games in the Tenchu series earned their black belts with engaging stealth action that challenged players to think creatively and use a variety of cool ninja tactics. Although Tenchu: Shadow Assassins mimics the format of its betters reasonably well, it never actually gets it right. The stilted controls and broken stealth logic not only make it hard to feel like a ninja, they also make it hard to have any fun. The solid visuals and stylish music can't mask the fact that Shadow Assassins is an exercise in frustration.
Tenchu: Shadow Assassins takes place in feudal Japan and brings back two protagonists that fans of the series will recognize instantly: Rikimaru and Ayame. The familiar kidnapped princess/kingdom in peril story unfolds twice, once from each ninja's perspective, and dovetails into a bizarre and surprisingly morbid ending. The cutscenes that tell the story are impressive, and you'll enjoy watching the detailed, fluidly animated characters play their parts in the serviceable narrative. There are some weird spots, notably the melodramatic voice acting and the Japanese merchant who speaks with a Cockney accent, but on the whole these cutscenes are a pillar of the generally impressive presentation. Environments are well detailed, and the musical score is an enjoyably modern interpretation of traditional Japanese themes.
Though you play as two different ninja, their abilities are identical. The gameplay consists primarily of sneaking through levels while killing or evading guards. Hiding in the clearly marked shadow areas will totally conceal you from view and let you instantly kill any enemy who comes within your reach. These quick kills, called hissatsu, require you to follow onscreen prompts and perform the corresponding remote motions or button presses. The satisfyingly brutal hissatsu are fun to perform and include such classic kills as snapping an enemy's neck and eviscerating him with his own sword. The cleverly designed stealth meter will help you stay hidden; it's an image of the moon that will shine brightly when you're exposed, cloud over if you're hidden, and is surrounded by stars that represent the positions of your enemies.
Staying in cover is crucial, so it's aggravating when the awkward controls hinder your movements. Both ninja move at a sneaking pace, which means that you'll do a lot of slowly walking between shadows (running will always attract the guards). Unfortunately, it's often unclear which environmental elements you can easily move through and which will impede your progress, which makes for some frustrating hang-ups. If you are close to cover or get spotted, you can shake the remote quickly to roll into cover or away from your enemy. This is usually a helpful move, but sometimes you may end up inadvertently rolling sideways into a fire or backward off of a cliff. You can also jump, which is useful for getting up into the rafters or onto a roof, especially given that the grappling hook from earlier Tenchu games is not available. However, the jumping motion is so jerky that it's best to rely on the onscreen prompts that tell you when there is a ledge overhead. Any attempt to jump around the environment is likely to meet with invisible walls or alerted guards, and the few times you have to jump over gaps are downright treacherous.
Ayame's Mind's Eye reveals an enemy just waiting to get his neck snapped.
You can use your Mind's Eye ability to spot guards, pinpoint shadow areas, and even see the guards' line of sight. If you are discovered and fail to dodge away quickly, you will be forced into a confrontation. If you don't have a sword in your inventory, you will vanish in a cloud of smoke and crow feathers, and then restart at the beginning of the area. If you have a sword, you will switch into a first-person view and fight the guard. You and your opponent switch off attacking and defending. You swing the Wii Remote to attack, and defend by positioning the remote according to the onscreen prompts. If you lose (which you often will), you'll return to the beginning of the area; win, and you'll deliver a death blow and go on your merry way. The remote is not very responsive in these encounters, and blocking enemy attacks is prohibitively difficult. Oddly, Tenchu: Shadow Assassins seems to want you to win swordfights only when it is required, so beating a boss in a duel is much easier than defeating an average foot soldier during the course of a level.