I’ve been viewing the “trailer” (perhaps “tech demo” would be a better term) for Valve’s forthcoming Portal with consideral admiration. It appears to be a first-person puzzler that breaks significant new ground in gameplay.
The idea is simple: Your avatar is equipped not with heavy weaponry but with a device that can open up portals in walls. Shoot one wall with the blue portal, another wall with the orange portal, and bingo—you now have the ability to teleport between the two. Indeed, if you stare into one, you see out the other. Wherever you place the portal pair, it becomes as though those two places are physically connected. Topologists would say that the portals “identify” the two surfaces with one another. Topologists would also point out that identifying parts of an object with other parts can create strange complex new shapes.
Thus, the trailer shows off all sorts of clever applications. What could you do, if you were a video game character trapped in a futuristic and hostile environment with such a device? You could open up portals to escape from dangerous situations by teleporting to safer ground. You could open up one portal in the floor beneath a crate and another in the ceiling above something dangerous, causing the crate to drop upon the thing and render it less dangerous. (Nota bene: crates as a genuine gameplay element! Perhaps not since Sokoban has it been done well.) You could open a portal at the bottom of a pit and jump into the pit—so that when you emerge from the other portal, you do so with significant momentum. And so on and so forth. (You can try out some of these ideas, if clunkily, in the game that caused Portal’s designers to come to Valve’s attention: Narbacular Drop.)
This game serves (or rather, will serve, I hope) as a fabulous example of working with constraints. Portal starts with a healthy respect for Newtonian and Euclidean principles, and then relaxes them in one, simple, well-defined way. It takes about two minutes of playing around or watching someone else play around to get the basic concept of how the portal gun works. After that, it appears that much of the game consists solely of figuring out how to turn the new laws of physics to your advantage. Valve did something similar, although I would say less ambitious, with the gravity gun in Half-Life 2 (which allows you to pick up and fling objects at a distance).
I hope that Portal does not lead to a slavish series of games with portals distinguished only by their window-dressing: one in space, one with cute cartoon fish, one with a Robin Hood theme, and so on. I hope instead that it spurs a new round of innovation in the somewhat long-in-the-tooth first-person-shooter genre. There are an awful lot of other tricks one could play with the laws of physics that would make for some neat gameplay effects: * Impossible Escherian space. (Prince of Pesia II had an Escher scene, but it was essentially two-dimensional; the paradoxical appearance of the space was merely a clever design that you had to force your brain to ignore.) Imagine a boat chase around the waterfall, or a tense sniper on the stairs of his Relativity. * Gravity warping. This what I thought the “gravity gun” would do when I first heard about it: create spots to which everything else was irresistably attracted. For advanced effects light itself could warp nearby. Imagine trying to correct for nonlinear space when lining up a shot. * Subtly wrong geometry. Five-sided city blocks come to mind, as do growing and shrinking rooms. (Bungie’s Oni subtly faked some of these effects by scaling characters up and down for a dream sequence.) You wouldn’t even have to change gameplay much, just introduce enough oddities that the player feels unnerved in certain areas. These effects could add significant effective suspense to a survival horror game, I think.
I don’t know that I’ll actually wind up playing Portal much, if at all (I haven’t exactly been buying my computers with an eye towards gaming performance), but it warms my heart to know that something like it is coming into existence. It’s the kind of admiring delight I feel when I view the trailer that made me into a gamer in my early years. It was a time of more ferment and smaller budgets, when designers would often throw out strange idea after strange idea until they found a gameplay mechanic that just worked. I have some hope that such an age may be dawning again. (Narbacular Drop was a student project, a fact that may be significant.) Let us hope.