Nonlinear and emergent gameplay is a goal that generally benefits game design, should the developers have the necessary resources. Making an open, vivacious world presents players with a lot of options and opportunities to find ways to enjoy the game, as well as letting them experience the joy of discovery without needing constant guidance.
I’ve always been a huge fan of roguelikes; they have huge play spaces and lots of depth to their mechanics, and what these games really accomplish so well that few other games do is the amount of discovery and gameplay they provide. A lot of this comes from the fact that they can be made with a really low production value. Dwarf Fortress’s creators explicitly recognize the fact that they couldn’t have made their game in 3d, or even with full 2d graphics, and still have time to actually develop the features they want it to have. GearHead is another example of a game whose gameplay was well ahead of its time, with customizable giant death robots that could be built to resemble almost anything the player put their mind to (including flying tiger-like creations or giant floating fortresses), with a wide array of weapons and armor choices for any situation. ToME had massive dynamic world elements, but I can still navigate Bree in my sleep and recount many tales about its surroundings and my adventurers’ fates.
It’s an experience that many other games have delivered as well. The Knytt series, for instance, is an exploration platformer that I also loved when I played it, but I’ve had similar experiences with games by Spiderweb Software or the massive expanses of The Elder Scrolls. This is because these games allow for two major elements; the aforementioned nonlinear discovery (or, at least, discovery that is self-guided), and emergent gameplay, though each of these is only available to a certain degree in certain games.
One of the greatest things a player can experience in a game is to have their discovery rewarded. One of the important things for this to really work is choice; players have to feel like they want to go somewhere without necessarily being forced to. For instance, one of the few issues I had with Tomb Raider is that I, a collection-happy gamer, was forced to double back and explore despite the fact that the game was pushing me forward. Morrowind is an example of this being pulled off spectacularly, with the player being dumped in a strange and exotic world with few restrictions on their exploration. One of the cores of discovery is this choice, though as a game designer you have several options to make this work; the common Metroidvania style is simply to provide paths that are out of reach and allow the player to naturally move through the places that are in reach, but this can be frustrating or confusing, especially if the only goal of the game is essentially to navigate this maze. Psychology can play a key role in this as well; Left 4 Dead was one of the first games to experiment with guiding the players with cues and getting known for it, but it managed to create a clear linear progression without using more direct guidance. As a developer, it’s almost certainly too much to try to create a fully dynamic open world with next-gen graphics and design, and even as a setting writer and creator it’s difficult to create a world that really teems with life. Working as part of a large team, there’s a chance to create some really impressive things, but there’s a reason why you only see a few massive masterpieces of this sort. Similarly, tabletop games like Shadowrun typically only include one major location in their core rulebook, if even, though games like Eclipse Phase have proven to undo this stereotype to an extent. The thing about discovery is that it must be done with great effort-exploring Minecraft once or twice is fun, especially when odd terrain features are discovered, but the best experiences are those that are hand-crafted; Firefall has some wonderful environments if you’re willing to dig through them then take a few steps back for a photo opportunity. However, few things can beat the classic ADOM or NetHack, with massive amounts of lore and opportunities to figure out what’s going on in the world around the player.
Emergent gameplay is one of those other “holy grails” of game design, and most games now rely on it to a certain degree. A game as complex as Dwarf Fortress presents many solutions to every problem. Not enough food? Easy enough to solve; build another farm, get a hunter or fisherdwarf out to take care of the issue, or just “accidentally” lock a few dwarves outside in the next goblin raid. It is, however, extremely difficult to build, especially around a static narrative experience. Players’ abilities to figure out what they’re doing is important in emergent play, and the ability to figure out optimal solutions to problems is a core of any competitive game. The strategy genre is built upon this; Command and Conquer did not have one single solution to victory, but rather many that the player could choose from without prompting, discovering their own way to conquer their objectives. Sometimes it’s a good idea to minimize the player’s toolkit to give them more guidance early on in the game, but other times you can just give them anything. Arma, as a series, sells on this concept, with the entire game being one big sandbox of military strategy that allows individuals to make smart decisions about their environment; Escape from Stratis was my most hectic experience in Arma 3, as I crept across rocky terrain hoping that the helicopter that just flew over hadn’t spotted me. This is the sort of decision making that makes a game memorable and worth playing-should I just avoid the pack of wolves in ADOM, or hunt them down and try to turn them into my next meal?
The important thing to remember about both of these is that they can be faked; presenting particular situations to the player will allow you to create a feel of realism and complexity within the game environment without requiring the high levels of content and mechanics design that are required normally. As a game designer, however, it is crucial to remember that cutting corners leaves gaping holes in your game; when playing Arma there are many ways to discover alternate routes and resources, but in a Call of Duty game with linear levels and a very small set of solutions, there’s not much that can be done.