Ah, the good ol' rose-colored glasses of nostalgia ... Tenchu was one of the first games I had for my Playstation console back in the 90's, then it was one of the first games I re-bought when I got my PS2 some years later. Now, after another pause of a few years, here we are together again. The thing about games that you take a long break from, is that you tend to just remember all the good times, while sort of filtering out all the bad/annoying qualities subconsciously.
Such is definitely the case with Tenchu, a game that, coming back to it ten years after its initial release, I have to admit has not aged tremendously well. It was a better experience when it was new and novel in 1998; however, that isn't to say that it is a fundamentally bad game, or even that it is not enjoyable now.
The game just has a couple of key weaknesses, mostly centered on the much simpler technology and sophistication of the 3D engines of its time. Namely, the camera is horrendous, and the play controls can be annoyingly slippery. Both of these weaknesses only really manifest themselves while in combat, however; this being a stealth game, you'll mostly be trying to avoid that combat as much as possible.
Tenchu was actually the first release of what is now thought of as the "stealth action" or "stealth" genre, beating Metal Gear Solid to market by a few months. You play the role of either Rikimaru or Ayame, ninjas in feudal Japan who go on various missions for their Lord (a dude named Ghoda who seems to be generally pretty honorable, at least relative to the social mores of the time and culture.) This version of feudal Japan incorporates mystical and fantastic elements, however, so in addition to Punishing The Evil Merchants (the best masturbation euphamism ever, BTW) by sneaking into their opulent compounds past their private army of guards, you'll also encounter a deranged cult that turns people into fire-breathing zombies, Tengu mountain demons and lords of Hell among other foes.
In all cases except for boss battles, however, these foes can be dispatched instantly if you get up behind them without being spotted. Depending on what angle you approach from, this leads to a cinematic "fatality" sequence where you slit, disembowel or generally break key parts of their body in some flamboyant way. If you are spotted, however, guards go into combat mode, which means you have to fight them fair and square and whittle down their health bar to kill them (or run and hide until they forget about you.)
Your basic equipment for each level is simply your weapon, and a grappling hook, which is used to get onto rooftops and sometimes to zip across chasms. There are also a range of bonus items you can find in the levels, and which you also get a stock of at the completion of each level; throwing stars, poisoned rice balls to leave on the ground for the dumb guards to eat, bombs, and caltrops among them.
There are only ten missions to the game, but there's actually a lot of replay value. Rikimaru and Ayame have to each complete the mission sequence on their own to unlock new levels; they also have separate inventories of items, which can be added to by successfully completing levels that you have already passed again. Each also has unique dialogue and voice acting in their cutscenes, and there's a slightly different ending for each one. They are also slightly different to play as; Ayame has weaker attacks and seems to have more trouble blocking and a shorter weapon range, but she moves faster and has a really nasty five-hit attack combo that is very damaging if the whole thing completes. Rikimaru is generally better at face-to-face combat and has a greater weapon range, but is slower and a little bigger and bulkier when it comes to hiding behind things. Most of your time will be spent trying to get the Grand Master rating on each level, however; this involves being spotted as few times as possible while performing as many "stealth kills" as you can. Each level, additionally, has three separate layouts which change the placement of items and enemies. So, provided you enjoy the game mechanics, that's basically six variations of each of the ten levels for you to try your hand at. Earning the Grand Master rating in a level also unlocks some sort of fun bonus toy to play with, such as Sleeping Gas or Flame Breath.
You see a lot of Forum Drama surrounding Tenchu and Metal Gear Solid; people seem to like to pick one side or the other and claim that it "pioneered" the stealth genre while deriding the other game as garbage. I find it hilarious that the Tenchu supporters always seem to cite "the genetically enhanced guards can't see 10 feet in front of them" as one of their common "talking points" in bashing MGS, given how incredibly dumb the guards are in this game. I'll grant that they can see a little better here, perhaps, but I would definitely not hold this game up as some sort of triumph of AI programming. The guards walk very repetitive, short patterns endlessly, unless they spot you. Or if they spot a dead body; for bonus hilarity, kill two guards near each other and wait for a third guard to get within range of seeing them. He'll run over, get all agitated about the first body, then eventually calm down - then he immediately gets agitated again about the second dead body, which he was likely running all over while he was worked up about the first one he spotted. Regardless, his eventual response is to Return To His Positions and keep repeating the same tired routine he had been doing before. For even more lulz, if a guard chases you and gets far from his normal post, then you hide and he forgets about you, he'll go back to doing whatever he was doing at his original post, except he'll start doing it at whatever random location he wound up at when he decided to stop chasing you, leading often to walking into a wall repeatedly. I could bring up more points, like how you can huck a rice ball right into their field of vision from a rooftop and they'll just grab it off the ground and scarf it down, or how they seem blithely unconcerned with sparking bombs landing near them, or how they never seem to bother to look up or down, but this is running long already. I'll just say that the challenge in Tenchu comes entirely from the placement of the guards in the level, usually from how to dispatch one while two or three are within sight of him and will notice you when you kill him. The levels are well-designed in this sense, and while getting through them isn't that hard of a challenge, getting Grand Master on all of them is pretty tough and will take you a while.
The guards are also not the most combat-capable, and even the bosses are pretty doofy. They have one powerful ally on their side, however - the cameraman. The camera tends to focus over top of you, which prevents you from seeing them. Successful combat in this game hinges on blocking attacks and then responding while the enemy guard is down; normally this isn't hard due to the lame AI, but when the camera is positioned half the time so that you can't even see the enemy, it makes it tremendously more challenging (in a cheap way). Another issue with blocking attacks is that you have to be perfectly parallel and facing the enemy's attack direction; one little slip to one side or another and you get hit instead of parrying. The controls make it easy to slide to one direction or another accidentally, however, so between that and the camera you often get diced up by attacks you should have easily been able to counter. Assigning the parry to a button rather than having you hold backwards would have cleared up a lot of this; that and the bad camera positioning (which you can't control manually) are the two major failings of the programmers.
Pretty much everything else about the game, however, makes up for the weaknesses. It actually goes a long way on ambiance alone; the game is an approximation of badass samurai movies coming out of Japan in the 1960s and 70s, and everything in the aesthetic down to the sound is designed to reflect that. For bonus fun, in the Western localizations, we get the cheesy dubbing and dialogue typical of those movies. I don't know if this was just due to the usual 90s practice of spending as little on localization and voice talent as possible or by design, but if by design it was a masterstroke, as the hammy lines and stereotypical accents are a major part of the fun of the game. The soundtrack also needs special mention, because it is really one of the best on the Playstation. Redbook audio is used for the entirety of the game, and the style is 1970s samurai movie crossed with both traditional Japanese music and modern symphonic. It all works out very well and the music has a very unique, memorable flavor.
The gameplay outside of combat is also pretty great, with a versatile range of moves for your ninja, from hanging on ledges and moving hand-over-hand to crouching and rolling to get behind cover. Only in combat do the flaws of the engine really become glaring, but outside of a few mandatory boss battles, you'll mostly be avoiding combat anyway.
* Gameplay Video