Location, location, location
It's becoming more or less unusual for modern games to focus on a single location for too long, quickly moving on to others and bombarding the senses with more and more prettiness. However, establishing a memorable location and focusing on it has often led to incredible games, and there are a variety of ways locations can be used to benefit a game. Below are a few examples to help elucidate this concept.
A changing location: Chrono Trigger
Chrono Trigger for the Super Nintendo is a game about time travel, which affords it the opportunity to show the world's evolution over a large span of time. The first picture in the slideshow shows the exact same spot at different times—notice how the land moves with time, with features appearing and disappearing. Chrono Trigger is still widely considered one of the best jRPGs ever made, despite the world being small, especially by today's standards; it's by focusing on the world and how it transforms (and how you transform it, as many of your actions affect things in later times) that the game succeeds. In being a witness to so many different faces of the same world and recognizing the similarities and differences between different time periods, the gamer can't help but become attached to the location. When done badly (such as in the case of a game mandating tedious backtracking in order to progress), the familiar can become an impediment, coming across as repetitive rather than nostalgic. When done well, however, the setting can itself become a character in the story.
A living, breathing location: Planescape: Torment
Many things can be said of Planescape: Torment. That there's a paucity of content in and around the game's central location of Sigil isn't one of those things. Sigil is packed with NPCs walking around and a surprising number of sidequests, and all of this bustling activity gives the city a real presence. That's to say that it feels alive, less like a game world and more like an actual city full of strange characters. There's something to be found on every corner, and while focusing so heavily on this one location may have meant an inability to pack the game full of too many other places, Sigil is so detailed and generally well-crafted that one can't help but miss it once they've left. Compare this to Dragon Age 2, where, despite it apparently being a city, very few people are ever around; this dead quality is so pervasive that it's virtually impossible to look back on the location fondly despite most of the game taking place in it. In fact, consider this: It's a very real possibility toward the end of the game that more people will appear in mobs during combat than normally inhabit the location you're fighting in. Between that and the lack of interesting things to do and find, Dragon Age 2 utterly failed to create an enthralling location like Sigil. It's about creating an interesting location full of surprises, dialogue, and miscellaneous details that catch one's interest—not creating a city and subsequently populating it with as few NPCs as possible.
A plot-sensitive location revisited: Dreamfall
Dreamfall didn't exactly do a lot of things well, but had it not captured the magic of The Longest Journey (pictured in the slideshow) by revisiting an old location and capitalizing on the memories of that place, it likely would have been an even bigger disaster. Had the story actually been coherent and well-written, that moment where you realize that you're in the same inn as the previous game would have been magical. With the game the way it is, it merely helped save it from sinking entirely. This does, however, serve to illustrate just how powerful revisiting a familiar location that has history can be. For those familiar with The Witcher, how much better would a future Witcher game be if it allowed you to revisit Kaer Morhen? Sometimes the very presence of something familiar from the past can better a game by bringing its emotional weight with it, even if it doesn't play a significant role.
None of this is to say that varied locations is a bad thing. Rather, the point is that there should be a balance between running through a location, never to see it again, and revisiting a well-designed area that the gamer will carry with them long after playing. As they say: Location, location, location.