Portal 是过去几年最具特色的益智游戏之一，它的续集 Portal 2 向我们展示了闪电可以击中两次。不到一年前，Valve 在《传送门 2》中引入了一个简单而强大的关卡编辑工具，再次掀起了波澜。在本文中，我将讨论如何设计具有挑战性的玩家的精彩谜题。
使用 Portal 思考
为 Portal 2 设计关卡与为其他游戏设计关卡非常不同。要为“传送门 （Portal）”设计强大的关卡，您需要对整个游戏玩法以及不同的游戏元素如何相互交互有深入的了解。在与关卡编辑器坐下来之前，您应该做一些准备工作，以进入正确的心态来考虑 Portal 关卡。
花点时间玩玩社区制作的地图，例如 Rendezvous、Only as Difficult as You make it 和 Suspended。并非所有的社区地图都是完美的，其中一些是艰巨的任务要完成，但这是值得的。一个简单的事实是，社区制作的地图比 Valve 自己制作的地图还要多，其中许多都非常不可思议。此外，手头有一个笔记本，这样您就可以记下拼图元素之间的有趣互动以及不同拼图的工作原理。我发现最好一步一步地写下一些更独特或更具挑战性的谜题的解决方案，因为它确实可以帮助我评估是什么让这个谜题如此有趣或困难。
《传送门 2》的 Steam 社区中心。
最后，花一些时间尽可能地了解《传送门 2》中不同的谜题元素。我发现列出不同的拼图元素以及当我工作时它们可以做和不能做的基本事情通常会有所帮助，因为它可以防止我忘记任何单个元素，并让我更容易地考虑元素之间的相互作用当它们都在我旁边时。
产生想法
我不会撒谎：想出 Portal 关卡的想法可能非常具有挑战性。与大多数其他游戏中的关卡设计不同，您的想法可能来自您想要的环境类型和您希望玩家实现的目标，而 Portal 关卡则完全是关于手头的任务 - 它们都是关于谜题本身的。
正因为如此，我发现想出 Portal 关卡的最佳方法之一是从您想要关注的解谜机制开始。例如，您可能是激光重定向拼图的忠实粉丝，或者您可能喜欢空中信仰板。无论您喜欢什么，确定您想要的拼图类型始终是一个很好的第一步，因为它可以帮助您更轻松地定义您要制作的拼图类型。例如，如果你打算在你的谜题中使用激光，你可能不会制作一个小的测试室，如果你打算使用白色凝胶，那么你的可传送墙可能会少于玩家解决谜题所需的数量，因此需要使用凝胶。
The tool box from the in-game editor, with all the available puzzle elements.
Another way to generate ideas for a puzzle is to think of the overall concepts you want the puzzle to involve or the actions you want the player performing. Maybe you want a puzzle with a large pool of water in the middle where the player is constantly going from one side to the other, or a chamber which is divided into quarters by two criss-crossing fizzlers. This is very similar to the previous method except you are now thinking in terms of the actions the player will be engaging in while solving the puzzle rather than the specific tools they will be using to perform those actions.
Overall, it's best to start with the broad strokes of the puzzle such as the main goal or actions by the player so that you have a guiding vision and the move on to the more specific details as you develop it. It will be much easier to figure out where to place the cube dispenser once you know what the cube will be used for than it will to try and figure out what to use a cube for when that's the only thing you have in your level.
Building the Level
Once I have the overall idea down I start drawing things out on paper or in a sketching program. While my drawings won't be perfect I still like to get a basic layout down so I have something to work from when I go in the editor and so I can start seeing how the puzzle elements may interact and can find the most basic problems quickly. I also use this time as another brainstorming period and try to think of multiple potential layouts that could all work for the same idea.
These are notes I put together while working on a level idea I'll be making in a future article.
With basic concepts complete, it's time to get in the editor and see how the ideas will actually work out. The great thing about the Portal level editor is that it allows you to use iterative design techniques very effectively so that if you don't like how something is working, you can quickly make the necessary changes and test the new version to see if it helped. This part of the process is the most ambiguous since no two people want the same things from their levels. While I can't tell you exactly how to build your level, there are some things that you should keep in mind that may help.
Challenging, Rather Than Frustrating
The first thing is the idea that your level should be easy to comprehend, but challenging to complete. A puzzle of any kind, not just a Portal level, is only fun when the player clearly understands their goal but is not necessarily sure how the goal is accomplished. If they don't know the goal, they cannot proceed and will only get frustrated, and if they already know how to complete it then there will be no challenge and it won't be interesting.
To make a good puzzle you must balance the player's understanding with the puzzle's challenge so they understand what needs to be done, but not the actions that need to be taken to make it happen. To avoid these issues, make the goal visible from the start of the level. When the player walks into the test chamber they should already have some idea of what they need to do. Even if they don't yet know how to finish the level, they should know what they need to do at that moment so they are not left pondering their first action for an extended period of time.
I can see my goal but I am not sure how to reach it.
Inherently Rewarding
Next, you want the player to have a sense of accomplishment when they complete your puzzle. From the player's perspective, the best part of Portal is the moment when they finally figure out how to solve the puzzle and get their solution to work. To give the player this feeling you have to make sure there is room to fail as well as to succeed. This boils down to how you use black walls, or non-portalable walls, vs. white walls, or portalable walls. If you have too many black walls and only have white walls in specific spots your puzzle will not be fun because the player will have no real choice in how they solve the puzzle or how they arrive at the solution. On the other hand, if you don't use any black walls it may open your level up for solutions you didn't intend which are much simpler or less interesting than what you had in mind when you made the puzzle.
Overall this issue is going to become most obvious through playtesting - so, as usual, do lots of that. It also just helps to be aware this can be an issue and to consider it while laying out your puzzle.
Author's Note: It was pointed out by a commenter on the YouTube version of this video that the white walls on the left and right should actually end at the point where the platform the player needs to get on begins. If they don't then the player is able to place a portal at the edge of the black wall and step out of the portal onto the ledge without performing a fling mechanic.
Editor's Note: I guess this underscores David's later point about playtesting being crucial!
Re-Using Puzzle Elements
The final thing I want to mention here is using puzzle elements in multiple ways. A lot of the most interesting puzzles I have played require you to use the same puzzle elements multiple times throughout the level and don't always make it obvious how many different ways, or what new ways those elements need to be used later on.
Now let's be clear, I'm not saying that if you are making a puzzle with lasers you should have multiple different laser emitters around your level and have your player use lasers a bunch of times, I'm saying you should try and design puzzles with limited numbers of each element and then force the player to go back to elements they already used earlier in the puzzle to use them again in a new scenario. In the video below I play through a level which does this in a simple yet effective manner and you can see exactly what I'm talking about.
Playtesting
Designing levels in Portal is a unique challenge. As I said earlier, it is different from many other games in that the attention is entirely on the gameplay and often if you try to add a lot of flourishes by bringing your level into Hammer (the standard map editing tool for Valve games), to use more unique textures and props, it may just distract or confuse the player. If you are building your level in the built-in level editor then the only things you have access to are the things that will affect the gameplay, so really nailing down those gameplay elements and making sure everything is just right is incredibly important. This is both a good thing and a bad thing depending on your perspective but really it's just a sign you should do a lot of playtesting.
When playtesting, do your best to find as many solutions to the test chamber as you can. Hopefully your test chamber can be solved the way you intended but you also don't want to limit your chamber so that that is the only way it can be solved. Specifically you need to find the ways the player can manipulate the rules of Portal so that they can solve the puzzle and skip what you intended to be the puzzle's solution. You may have issues like this because you didn't eliminate enough of the white walls like I said earlier, or because you didn't realize the player would be able to get a second cube onto the other side of a fizzler - whatever the problem is, you need to find it.
I find during this stage it really helps to bring in other players. Everyone thinks differently and you will never think of all the solutions ten of your friends will in the same amount of time. In the end you really just need to playtest as much as you can until the only solutions available are ones you are happy with. Also remember, just because a solution is not the one you intended, it doesn't mean that solution is bad; don't cut it just because it's not "correct".
Closing Remarks
A lot of the Portal design concepts may be hard to grasp at first because puzzle design is a somewhat complex subject, but as always practice makes perfect. I hope this article helped you get a sense of how to design levels for Portal and what you need to consider, but if some of the concepts still seem strange to you, make sure to come back soon for my step-by-step guide here on Gamedevtuts+ where I'll design a Portal level from the ground up and explain the reasoning behind my decisions.
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