Games, movies, and magic have one major thing in common – misdirection. Show people one thing, then indicate to them that they saw another, and usually they'll believe you. In magic, it's harder because they're trying to figure out what you're doing while you're doing it. In movies, it's easier because the person is really just going along for the ride. In games, it's really easy, because the player is being assaulted by zombies and doesn't have any attention to spare.

At least, they don't the first time they play the game.

The second time, they're probably paying a lot more attention to what's going on around them. The zombies attacking, yeah, sure, they're a problem – but we've dealt with them before. Let's look at the other things around us!

This is when they discover how careful the game is at showing you exactly what they want you to see, and keeping you from doing anything besides what you're supposed to.

Not supposed to go through a door yet? It's locked. Got a cutscene to watch? I can guarantee every door leaving that room is locked – even if you just came through it ten seconds earlier. You can walk through a door, have it lock behind you, and then have the very same door unlock the instant you're done with a cutscene or a movie. Happens all the time.

Sometimes they even force you to look in certain directions. Sometimes, this is to make you look at something you're supposed to see. Sometimes, this is to make you look away from something you're not supposed to see. In the first level, there's an exploding shuttle. I bet you remember seeing it explode, right? It was really cool? No! You didn't. Because you can't have. The camera is jerked away from it at the last second, and when you turn back to it, it's already exploded. You're carefully prevented from seeing the exact moment it explodes.

The reason for that, of course, is that animating something large exploding in a realistic manner is expensive and hard. It's easier to just not show it. And it works great . . . up until the person realizes what's going on and decides to try exploring the boundaries.

This is a common issue in games. There are a good number of games out there that pretend you're given choices, but actually prevent all choice. The Half-Life 2 series is a perfect example – the first time you play it feels like an exploration, but every time after that you realize, hey, wait, I'm not allowed to go anywhere else! That exploration feeling was a ripoff!

I should mention that this is not necessarily a bad thing. The fact is that most people will never start a second playthrough – in fact, many people won't even finish the first. It's arguably kind of silly to triple your budget by making content that 95% of your users will never even see. (It's also arguably not. I'll post an entry about this someday.) But it does mean that going through the game a second time is kind of like being invited backstage at a live performance, or having the magician explain his tricks – all those cute things you noticed the first time turn out to be your own fevered imagination running a bit too fast.

Solution? There isn't one, besides solving the hard AI problem and writing programs that can generate content for us. Unfortunately, this is a ways off, and if we ever do solve it, we've put ourselves out of a job.

All I can say is: be aware of it, and try hard to keep the player from feeling constrained. At least, on the first playthrough.

Dead Space takes place on board the the USG Ishimura, a colossal "Planet Cracker"-class mining ship. It's a ship designed to literally rip apart planets to feast on the tasty, tasty ore inside. The ship's architecture varies from tight constricted maintenance corridors to huge open industrial spaces. At various points you visit the hydroponics bay, personal quarters, the medical bay, the bridge, and pretty much the entire set of possible important ship locations.

Most of the places you travel make sense in context of the ship's purpose. There's equipment suitable for its purpose, the layout is at least plausible, the lighting looks like it would be acceptable before zombies smashed up the place, etc. Some of the places do not make such sense. The ship is weirdly infested with inexplicable circuitous corridors. There are industrial areas that can best be described as mazes of walls. Why is there a maze in this ship? Did the crewmen just want a maze in their ship? There are strangely-placed high-speed trams that lead from one near-dead-end to another (the asteroid cannon being the most notable WTF moment). Why isn't, you know, there just a door which is closer? Are you seriously saying there aren't any other corridors within a kilometer? Overall, a good chunk of the ship just plain doesn't make sense.

Now, if the ship were designed by zombies – yeah, sure, go for it, zombies are crazy, who knows how they'd design it. But they aren't. It was designed by people. And when you're told that you're walking throughout a human-designed spaceship, and 3/4 of the ship makes perfect logical sense, those moments when you find yourself thinking "wait, why does this area even exist?" are painfully jarring. Why does this maze exist? Well, it exists because the game plans called for a maze, and by gum, we're putting a maze in!

What's the fix?

The only fix I can think of is to be excruciatingly careful that each location makes perfect sense, both for the game and in the context of the universe. It's hard, it's really hard, but I think it's important. This isn't an issue that's restricted to games – it's something movies get constantly wrong as well (please, explain to me why the Emperor's chamber on board the Death Star has a hole leading directly to the reactor core without even a guard rail) – but that's not an excuse, it just means we get more people to laugh at when we finally get good enough to avoid it.

For each zone, for each object in the game, you have to answer two questions. Why does the game contain this? Why does the world contain this?

If you can't come up with good answers to both questions, get rid of it.

Traditional game animation is (mostly) pregenerated. An animator sits at a computer and carefully poses the motion of each limb. Eventually, you have a spider that crawls across the ceiling and shoots acid in your face. Done!

In motion, this looks pretty good. In death, it's problematic. First, unless you've gone to the trouble of multiple death animations, creatures always die the same way. If you kill five hundred Basic Guards, you'll end up with five hundred identically-posed corpses lying around. Uncool. Second, death animations have nothing to do with the weapon you kill them with. Poke them a thousand times with a needle? He'll scream, fall over, and lie with his face on the ground. Shoot him with a portable nuclear warhead launcher? He'll scream, fall over, and lie with his face on the ground. Uncool. Third, death animations tend to "snap" from other animations. Basic guard takes a flying leap, jumps at you, you kill him midair . . . and suddenly he plays the Death Animation, which involves him instantly standing up in midair, then screaming, falling over, and lying with his face on an imaginary ground, while his corpse eventually falls into a pit. Uncool.

There's a solution to this. Games have gotten sophisticated enough that most modern 3d games include a basic physics engine. You don't need perfect physics for this, something simple is pretty effective. Animations are already based on a simple skeletal model – arms have two "bones", legs also have two "bones", etc – and it's easy enough to allow these bones to just move via the laws of inertia and behave properly on impact.

So you kill someone on a tower of boxes, his corpse will tumble down the boxes. You shoot someone with an air cannon while he's standing in front of a railing, he'll backflip over the railing. Rocket launcher to the feet? Flying guard corpse! Cool.

There's problems. (Of course there's problems. You think I'd be writing about it if it really were that simple?)

Ragdolls tend to be used only for actual death. It's just too hard to recover from a ragdoll collapse if the creature isn't actually dead. You knock a Basic Guard into a pile of boxes and he gets jackknifed between two – how does your Basic Guard recover from this? He doesn't, but now there's a living Basic Guard jammed uncomfortably into a pile of boxes. It doesn't work well. So ragdolls are only used for death.

But that introduces a new, irritating problem. Ragdolls can be used to detect death. Dead Space includes a gun that fires a shockwave which knocks things down. When knocked down, a lot of the zombies will cheerfully play dead, only to eviscerate you when you turn your back on them. However, it's trivial to determine if they're dead or not. See, when you knock them down, they always fall on their backs, with their legs facing you, and their left leg (from your perspective) slightly lower than their right leg. I know this very well from knocking down dozens and dozens of zombies this way.

When I see them fall down this way, I know they're just going to get up again in a few seconds. When I see them fall down any other way, I know the ragdoll mechanic kicked in, therefore I know they're dead, and therefore I can forget about them.

It's not very suspenseful.

I'm not sure what the solution is. It really is incredibly hard to recover smoothly from a ragdoll-based collapse. On the other hand, unless you have your artists make dozens of death animations, it'll always be easy to distinguish a "real" ragdoll death from a "fake" non-ragdoll death.

But it's a problem, and in a game like Dead Space, where detecting Proper Death is a very valuable skill, it's distracting like you wouldn't believe.