There is a good serie of columns on Gamasutra lately about level design by Sam Shahrani. It focused on FPS and 3D level design. What is good is that it gives a comprehensive overview of the different techniques used so far.
Some very relevant excerpts about how level designers takes advantage of constraints to create spatial affordances that would support the game scenario and gameplay:
Level designers, or map designers, are the individuals responsible for constructing the game spaces in which the player competes.
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The level design for Battlezone was relatively straightforward, in as much as it consisted of creating a game space (the “large valley surrounded by mountains”) in which the player could drive around and destroy targets for points. Essentially, the level design was that of a digital Roman arena, wherein the player could do battle, and it was a design that worked well for the limitations of the graphics engine, and provided enjoyable and novel gameplay for the arcade and home computer markets.
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Not all attempts at 3D games involved the use of polygon-based 3D environments like those used in Battlezone; several games attempted to leverage other technology to provide an impression of a three-dimensional world. Notable efforts include Lucasfilm Games, now LucasArts, 1986 title Rescue on Fractalus!, a first-person title that used fractal generation technology to render the game world.
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[Then in 3D FPS like Wolfenstein 3D]The emphasis on speed, however, again led to limitations on how detailed the world was.
Interactivity in Wolf3D was relatively limited, with the player having only two ways to interact with the world; shooting things to kill them and opening doors by pressing the spacebar, a universal “use” key. Wolf3D upped the ante, though, by adding in “push walls”. These walls appeared like any of the normal solid walls in the game, but if a user hit the spacebar in front of them, the wall would slowly slide back, revealing a hidden room (Kushner, 108). Hidden rooms and secret levels would play a major part in future id games, and First-Person Shooters in general. The push walls were another innovation by Tom Hall, who served as the director of Wolfenstein 3D (Kushner, 108-112), and served to reward the player for thoroughly exploring the game world. It was an interesting gameplay mechanic, and one that grew out of a tradition in the video game industry for including secrets, or “Easter eggs” for players to find (Kent 188-189). While many would consider these “Easter eggs” to be afterthoughts, they present an important opportunity for level designers to maximize player investment and interest in the game world.
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Doom fundamentally altered the First-Person Shooter genre (...) The Doom engine supported a number of new features that finally made realistic and interactive environments possible. Instead of merely featuring doors that could be opened, Doom featured the ability to alter the game world by using in-game switches and “triggers” to activate events. These events could range from a set of stairs rising out of the ground to unsealing a room full of ravenous near-invisible monsters to bridges emerging out of toxic slime. Additionally, Doom added in lifts, which could raise players to different levels inside the game world or, if used slightly differently, could act as pistons and crush players against a ceiling. Further, the Doom engine’s support of variable height floors and ceilings also meant that in addition to being able to move on all three axes, more complex architecture could also be created. Tables, altars, platforms, low hallways, ascending and descending stairs, spacious caverns and other objects could all be created using geometry.
The ability to trigger events that could release monsters or alter geometry led level designers to create a number of surprisingly complex traps for players to uncover as they played through the game, from rapidly rising floors to bridges that would sink into toxic sludge if players moved too slowly. (...) In addition to architectural advances, Doom also added the ability to alter the light levels in a level.
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The level designs for Doom were accomplished using much more advanced tools than previous id titles. Romero wrote an engine-specific level editing program called DoomEd
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Doom also illustrates that levels do not have to be based on easily recognizable locations in order for players to enjoy them, nor do they have to conform to preconceptions of what an environment should look like.
An important concept is also this idea "Doom defined the first person genre, but more importantly
it made the idea of users modifying a commercial title acceptable to developers.": the level design is the cornerstone of bottom-up innovation in the game world: through modding, end-user manage to create their own version what would be the world they want to play in.
Why do I blog this? What's explained here is of tremendous importance for the comprehension of spatial practices in virtual worlds. The author of this piece is Sam Shahrani, an M.A. candidate at Indiana University in the Master’s in Immersive Mediated Environments program through the Department of Telecommunications. He's making an incredible job explaining level design from the game developers' perspective. I am looking forward reading his dissertation.
It's certainly the most interesting piece about spatiality in video games I've read in the last few months.
Why do I blog this? It's interesting to see that it's a way to repackage existing devices. This is the same phenomenon as the 
Why do I blog this? these elements are very interesting and have a wider impact than just video game design. It made me think of the 
