Creating the illusion of non-linearity



Most games are linear. Even "open world" games like the original Zelda appear to allow the player to go about the journey as they please; however, you must first go through dungeon 1 to get the item necessary to access dungeon 2, then complete dungeon 2 to get the item needed to access dungeon 3, etc. In most RPGs you have a world map from which you can access any town or dungeon, but it is usually sectioned off to require that the player go through areas in a certain order. Between dungeons you may have the choice of visiting a town to buy items/rest/accept a quest/etc., but that is usually the extent of the non-linearity of a game's structure (until the player gets a vehicle that allows them access to the whole map at the end of the game). The feeling of non-linearity comes from wandering around and figuring out what you have to do in which order. This usually requires navigating twists and turns and backtracking through them a few times.

This post will go through my process of designing a temple I tried to make appear non-linear, although it is actually very linear. The temple is a bonus dungeon in my project "The Epic of Gilgamesh", which you can read all about on my website, Gilgameshgame.com. You can download a demo of this level by itself here,and I've included screen shots at the bottom. I'd appreciate feedback on my process and the level itself. Feel free to ask me to clarify anything that is poorly written.

The Concept

I started with the idea of a temple with two floors with two wings each and a basement. The temple contains four bosses and the player must defeat them all before they can access the goal. Here is the skeleton I started with. The colored dots are bosses and the gray letters represent connecting flights of stairs (so A on F1 takes the player to the A on F2 and vice-versa):



Pretty simple and boring, right? But this is what you'd expect a temple to be built like: symmetrical with easy access between floors. The basement is slightly more intricate since basements are usually used for storage. An actual non-linear approach to designing this would be to give the player free-reign and let them defeat the bosses in any order they want. The benefit of that approach is that the player has to figure out on their own the best order to beat the bosses (as in which is weakest/strongest or if the bosses grant skills/items/experience points which would be helpful in defeating the other bosses.), ala Mega Man style. However, because the temple is symmetrical, just finding the bosses would be pretty boring.

So how can I make navigating this simple dungeon interesting? I tried adding locks and keys. By blocking off some of the doors and having each boss drop a key, I can create a critical path that the player must follow to beat the stage. Locked doors let the player know they will eventually have to come back to that area, which means they must make a mental map in their head, and keep up with what keys unlock which doors. Here is what the dungeon looks like when I added locks and keys. The colored lines represent locks, and the corresponding dots now represent bosses and the keys they drop (the color of the boss/key corresponds to the color of its locks):



Can you figure out the critical path? Take a minute and try. The player has some options, but could easily get through the level without having to backtrack through previously explored rooms more than a few times. There can be slight variations in the path in terms of backtracking, but this example of the critical path roughly follows the alphabetical order of the stairs (the player wouldn't know that though, as the stairs are not actually lettered in the level and this map was just for my reference):



The critical path is the most direct route to the player's goal. But in this dungeon, the player would not know which way to go without checking the doors and exploring through trial-and-error. Notice the critical path does not require going through every room: these are where I placed my good treasurer chests, since they are not required (though the player may find them by accident while trying to figure out the critical path).

To make things even spicier, I require the player to answer ten questions based on facts given by ten NCP's spread throughout the dungeon to access the final goal (in addition to getting the final key). Here is how I laid out the NCP's:



So now the player has people to talk to as they explore, has an incentive to seek these people out and remember what they say, explore every room and to backtrack if they need to.

Finally, here are some examples pulled from my final product, just so you know what it looks like:


Spliced together image of F1 west wing (actually 5 maps)











I hope this is helpful...if not, please let me know what doesn't make sense and how my design can be improved!

http://gamedesignreviews.com/reviews/sword...a-world-design/

Referring to this, I'd think your way of making it non-linear is more making it a very controlled network. You have x amount of areas, and you could go through them as you'd like but ultimately you need the "key", "weapon", "spell", "plot point" in order to proceed to the next section. As said in the article, earlier games, especially non scrolling ones and the ones that are more action rather than turn based oriented, tend to do this more.

I would believe that Zelda is actually less linear than you think it is... but I haven't played it so I can't speak with authority on it. I was just of the assumption that you had more freedom and could do certain dungeons and things out of order and even skip certain sections/items altogether. At some point, you do eventually have to do x to proceed, but it's not a straight line in how you get there or how you approach it.

Non-linearity like that can actually be a bit of a pain if you're using random encounters, particularly if they're frequent which is why I might suspect they do it. With things that can prevent or delay or just avoid encounters, it's not an issue, except for those who still don't like getting lost.

Having played through the 2 Zelda games on NES, the one for SNES, the first on the N64, and a couple of hand-held installments, I have to agree with rewells. It is perhaps a lot more open than traditional rpg's, and generally you have access to 2 or 3 temples at any given time, but usually you can't finish them in any order you want, and you always have to complete all the temples (ie., get all crystals or triforce pieces or whatnot) before you can venture on to the last dungeon.

In any case, I like the term "controlled network", which is essentially what it is. Even MMORG's need a sense of order. A true open rpg is hard for anybody to make, let alone a stand alone game developer, but I think rewells is hitting it at the right angle, as you need to plan out the network before you draw the map. Sure, some people can just throw together a dungeon in RPG Maker with little to no effort, but it takes more planning on the developer's part to be able to plan accordingly and plot out the traps and puzzles.

That said, I'm pretty impressed with your mapping here; it seems you've come along way since your first Gilgamesh game.

@ Oceans: Thanks for the article. I also really like the "controlled network" concept and see that's pretty much what I set up. I think the first Zelda just appears to accomplish this much better because the overworld map is painstakingly constructed, but you don't actually have access to all areas in any order you want. I can't think of any rpg that lets the player do levels in any order they want like the Megan Man series, which is a series of non-linear choices of very linear stages. Could be an interesting design challenge.

As for random encounters, I always set them kind of high (50 steps per battle) but try to adjust for each individual dungeon so exploration doesn't get annoying...it's always a guessing game for me though since I know where to go :-) which is where having other people playtest helps.


@ amerk: I've beaten most of the Zelda series including the NES titles and while the first is a little less linear, the more recent titles have become extremely so. I read a critique of skyward sword (the new one for wii, which I haven't played) which argued that most of the obstacles were lock and key puzzles, with bombs and hook shots being keys and cracks in the wall and grabbable ledges being locks. The article Oceans noted (or one of the one's linked to it by the same author) made a good point about key-item functionality, that the items in zelda have multiple purposes (bombs open pathways and harm enemies, torches light dark areas and can be used as a weapon, etc.). The God of War games are super linear but do a good job of making items needed to overcome obstacles be helpful in combat as well. I think that is an example of good design.

And yeah, I've found planning the level with pencil and paper skeleton's to see how the entire dungeon connects makes mapping a billion times easier.

The way I like to wrap my head around an interesting non linear design is offer choice. Say you have a dungeon that has a door blocking your path. You study the door and see that it is made of a material that can easily be destroyed by the sap of a particular plant. You also notice it has a keyhole and see that it needs a key to open. As you investigate some more you find a recipe to craft a magical device to spot hidden doors. Which the hidden door will then lead you into the room for a sneak attack on the enemy boss.

Ofcourse this is a lot of work, but if you keep the branches simple and limit these choice puzzles to one per dungeon level, it can bring that much more diversity into an otherwise boring linear experience.

Note: My pictures are down because I couldn't afford upkeep on my old website's domain name (gilgameshgame.com) :-X I'll start hosting them elsewhere.

Good ideas...a simple but effective example of something like that would be the first level of Mario 2 (the American version with the vegetables), where there's an alternate path to the end that allows you to sneak up on the boss. It immediately screams :"This game is big and rewards you for exploring! So keep doing it!"

Once you hit a 100 posts, you can have your own gallery here.

This article talks about how Zelda I was actually very linear, but because of the geniuses at Nintendo, they did an illusion to make it seem nonlinear. Here is the article:
http://www.gamasutra.com/view/feature/1349...vel_.php?page=1

Thanks for sharing that article. I remember playing both Zelda games on the NES back when I was only 11 (it might have been). Both games were frustrating, but there was a sort of charm felt in the very first game that was never fully captured in any of the other installments. Primarily the focus was on dungeon crawling and less so on story, and as a result I think the game play showed, especially considering the features that would soon become a staple was a first for this game.

I definitely agree that it seems very open and not quite so linear, especially since you aren't really blocked from every new area. Where it becomes more guided and structured is the fact that, while you might be able to visit Dungeon 3 before finishing Dungeon 1, you might need an item from Dungeon 1 in order to do so. Or while you might be able to bomb through multiple places early on, you may be blocked from further progress unless you also have fire.

The game allowed unlimited exploration up to a point, but then you had to go back and take care of previous things to move on. Very clever in their design, I say.

Of course, finding the dungeons is another thing entirely, and one that could have been a bit less frustrating.

Funny but I actually enjoyed looking for the secrets places and hidden items the most in Zelda. Wondering around, Bombing and Burning everything in every farthest corner I could reach just to see if something new would happen. Sure, it caused my play-time to be extended by a few hours but it was time well spent, imho.

It's actually what I still look for in games I play today. I love to spend extra time looking in far corners of maps, looking for hidden Treasure and/or Easter eggs (is it any wonder why Easter was my favorite Holiday as a Kid?)

I don't know it seems a really interesting idea but I was wondering why the keys have to be sequenced to a certain door?It seems to me if you simply made it where each boss drops one key and that key can open any of the other doors but disappears after use that you would essentially have what you originally wanted.A open ended dungeon which you can tackle any which way you want.You could even have a symbol representing the kind of boss you will find there at the entrance.Like for instance if your four enemies were elemental type enemies a symbol for each of the four elements at the front of the entrance would allow the player to figuring out which one he would want to tackle first and so on. Now I might be missing something with the pictures no longer showing but that's my take on the concept.

I don't believe it's an illusion.

Non-linear does not necessarily mean non-causal. Non-linear basically just means an open world where you can wander rather than being herded. Final Fantasy X is linear (in fact this is a major plot point, that Yuna is forced on her mission) and makes no attempts to be otherwise, but the endgame allows some flexibility. Non-causal means events are surreal, and do not follow normal laws of consequence. That is, a completely open world where nothing you do affects anything is not non-linear, but non-causal (non-causal games usually suck). Skyrim is cool because it's huge and open ended, but there are still working quests.

That is, should you decide to do things out of order, there have been planned events in terms of change. Secret of Mana is a good example, you have just in the first section, Pandora and Gaia's Navel. You can go to either one, and there's no illusion, the consequences are there. But, it's more complicated than that.

1. What usually happens is, you go to the Water Palace, get attacked by goblins and saved by the Girl, go to Pandora castle, and talk to the girl and she joins the party. Then you go to Gaia' Navel, she says she wants to fight Elinee at the Forest. You go to the Forest and need an axe, so you head back to Gaia's Navel joining up with Sprite in the process.
2. You can skip the girl, taking a cannon ride to Gaia's Navel. The Sprite joins first. Then you can probably head back to the castle in Pandora and pick up the girl.
(These are the two most common approaches, that everyone knows about)
1b. The girl joins the party, only to leave in a huff when you try to drag her into Gaia's Navel before she knows about the axe. You have to head to the forest to pick her up (there's some battle where she's trapped and you fight off beastmen).
2b. Sprite joins first, you instead head straight to the forest, again fighting beastmen
3. This one's weird. Before going to the Water Palace and being eaten by goblins (if I remember, there's a trick to it, like not talking to Dyluck's crew or something), head to Pandora. You'll find the path is blocked off from the front. But taking the cannon to Gaia's Navel and walking back allows you to enter from the side. You can meet the Girl before she saves you from the goblins! But, since she hasn't met you, she doesn't stop to talk to you, and pushes you out of the way! You have to get the Sprite first and save her in the forest.

Regardless, you have your party fitting together, but there are many, many ways to do it.