IA Logo

IA Information

Dave Mark's books

Post-Play'em - Observations on Game AI

Posts Tagged ‘Tenchu Z’

Tenchu Z: Ninjas Had It Easy

Saturday, June 28th, 2008

I will preface this commentary with three things:

A) We got a copy of Tenchu Z for free.
B) My 13-year old step-daughter (a black belt in taekwondo) is enamored with ninjas and the like – which is the only reason why I even broke the seal on this game.
C) I didn’t get too far into the game – so if it gets better as it goes along, I missed out.

I can write off the game design itself as perhaps being “not my style”, but from an AI standpoint, this game is just plain bad. Even my step-daughter, with her rudimentary knowledge of game AI (just from being in the same room with me often enough) was pointing out the obvious issues it has.

Advertising States

First off, welcome to the land of plainly exposed finite state machines. The enemies may have well been traffic lights since they were broadcasting the very few states that they had. I haven’t touched the game in a few weeks, but off the top of my head, they were… Pace, alarmed, sniff (yeah, sniff), chase, fight, panic, die. Sure, there were some sub-states in there, but those were pretty much just to animate the characters.

What’s more, some of the states were not even necessarily dependent on the environment. I watched two guards arrive together at a point, stop, give a brief salute wave to each other, chat, turn and go back to pacing. I thought that was at least minimally cool. But then, one of the guards got distracted and was behind the pace of the other quite a bit. Well, being a stealth game, I was fully comfortable sitting in the bush and watching. When guard B came back to the previous meeting point, once again he waved, just like he had when he had been face-to-face with Guard A. After the predetermined period of time, he walked off again. Who the heck was he waving to? My guess was that the “meeting point with wave” was either embedded in the map or, more likely was just part of the patrol pattern of that guard. This is based entirely on the premise that the patrol patterns were timed so that they would meet up. Nice try… but dude looked kinda stupid.

Machine Forgetting

Never mind “machine learning”… how about “machine forgetting?” The premise of a stealth game is that, if you arouse someone’s suspicions, they will investigate. However, if you go dancing around in the open and people see you, the gig is probably up. Not so, in Tenchu Z. Apparently, a little-known fact about ninjas is that they possesses the ability to perform the Jedi Mind Trick. (I link this only because I was startled that it had its own Wikipedia entry. Wow.) You can literally mow down half the compound, run around the corner, and all remaining sentient beings will cease to remember your existence. In fact, you can come up just short of killing someone and even he will forget from whence he received his wounds. It’s like someone spiked their sake with GHB.

Also, they don’t bother to really look for you in more than 2 dimensions. You can leap onto a roof in full view of an entire legion of samurai, and in 60 seconds they won’t even consider the idea that you could still be up there. If you crawl under a building in front of everyone, they can have the building surrounded but will refuse to bend over and look under the building. Oh… and then they will leave so you can get out from under the building that they had you completely trapped under. Spectacular.

Now I suppose that some of this may have been a design decision so as to make the game a little more accessible to the “Dragon Ball Z“/”Naruto” crowd, but it is so striking that it is laughable.

Sensory Stimulus?

I’m not sure exactly what they are using for a sensory system. There is a light meter that shows how illumnated you are. That would be an easy coefficient to apply to a detection rate after LOS has been established. You can move quietly which implies that sound transmits – but I’m not sure if it is just a strict radial decay or if there are environmental factors. Of course, rice paper walls transmit sound through them like a drum head. There’s some sort of “smell factor” which is probably also just a distance factor as well. I did get a kick out of how the guards are so demonstrative in their sniffing (you can fall into nasty stuff and smell bad until you wash it off)… but the doggies that occasionally appear in the game can’t track you in a freakin’ bush 2 feet away.


The combat animation is very schlocky. Maybe I’m just not good at hack and slash games on the console, but it quickly turned into a button mash for me since I wasn’t entirely sure that anything I did was more impressive than anything else. The actual contact of a sword stroke was vague and there seemed to be pre-defined kill animations that involved the positioning of both characters. Let’s just say you should stick with the stealth because the combat system is less than stellar.

The Solution?

When I started writing this blog, I wanted to make sure that I offered up solutions to problems that I noticed. However, I don’t know if that is in order here. One of the major improving points would have been to simply spend more time on it. There are plenty of resources available to get past these issues. Many of them could easily have been addressed.

It is at times like this that I wonder if I can truly blame the AI programmer. Again, as I mentioned before, it may have been a design decision that the experience was not going to be deep and/or challenging. It also may have been a production decision based on time and budget. I can’t think that it would have been based on available clock cycles since their graphics don’t look like they came close to taxing the 360. So… it either comes down to a low-priority item for them a sub-par effort by an AI guy.

Add to Google Reader or Homepage

Content 2002-2018 by Intrinsic Algorithm L.L.C.