作者：Daniel Cook

我们在10月份发行了iOS版的《蒸汽战鹰：幸存者》，经过重新调整，游戏设置更加适合iPhone。除此之外，针对于iPad而扩展后的HD版本是我最喜欢的一个版本。其次便是Android版。所有的这些版本都是免费，所以不妨试试这款游戏，并告诉我你们的想法。

尽管这次新版本的《蒸汽战鹰》沿用了网页版的名字，但是因为与Halfbrick（游戏邦注：澳大利亚独立开发商，因为创造了《水果忍者》而出名）展开了合作，所以我认为iOS版本的《蒸汽战鹰》算得上是一款游戏大作。

通过添加新任务而完善游戏进程系统：游戏中设定了64个任务，其中有8个属于无限生存模式。如果你喜欢《蒸汽战鹰》，并希望能够一直游戏下去，那么这次的iOS版本便是你的选择。（有时候，比起一小部分智力关卡，你也许需要一些更深刻的内容。）

steambirds Survival(from casualgirlgamer.com)

免费游戏：这是我们在手机上发行的第一款免费游戏。与我们的大多数游戏一样，我们总是很重视游戏中的“免费”环节。我希望玩家是因为喜欢游戏而购买游戏。我很好奇我们能够从中学到些什么。

多飞机控制模式：我们添加了一个有趣的招募系统，让玩家能够招募到更多可被控制的飞机。带着三个“Chickadees”而通过一个关卡真的很有趣。以前的飞机，就像“Cockroach”都较为无力，而现在在多人飞机战略下则变得更加吸引人了。

新的能量增强机制：你可以召集NPC与你合作，一起战斗。为玩家展现出了一种史诗般壮观的游戏画面。

你的游戏是否拥有清晰的“箭头”？

当我们发行了网页版的《蒸汽战鹰：幸存者》后，我们并不满意它的任务结构。当“开放”和“选择”运作良好时，我们以为这是一个不错的主意。但是，当我们发现很多玩家都乐于挑选飞机，并在找到自己喜欢的飞机后花费游戏虚拟货币“cooper”去完善这些飞机。而这样便导致游戏缺少足够的前进动力，而使得玩家很难回头尝试其它不同的游戏玩法。

在新的任务结构中，玩家每次挑战都可以打开一个新的城市，而每个城市也都会为玩家揭开更多不同的城市。而在每个城市中也都设定了8个次要任务，帮助玩家提高级别以通过任务。现在，关于那些已开放城市的方向都很明确，而这也让玩家可以选择短期或者长期目标去完成相关任务。

在物理学中，著名的物理学家Arthur Eddington曾经用“时间箭头”这个短语描绘时间是按照单一方向而出现。当涉及到广义相对论的时候，你将会意识到时间是可被压缩的，并且能够按照各种不同的方法去操作它，特别是按照接近光的飞行速度。然而即使方法再多样，时间总是一如既往地朝前进。

而当我提到设计，我总会问道“什么才是游戏的箭头？”这是关于机制系统的定向性问题，即总是能够推动玩家向前走。与时间一样，“游戏箭头”也具有多样性，并且也是朝着同一个方向而变化。游戏玩家前进的速度较慢，也有一些玩家选择走奇怪的路径，但是不管怎样，他们的方向都是一路向前。

创造“游戏之箭”的工具

在《蒸汽战鹰：幸存者》中，各种各样的系统产生了不同的游戏之箭。

不可避免的衰退：飞机的寿命总是会衰退。虽然游戏中有一些罕见的提高寿命值的方法，但是它们也只能起到暂时的缓解作用。

难度提高：随着时间的发展敌人慢慢增加。波动范围越来越大。玩家与敌人交涉过程中遇到的困境越来越多。甚至是最优秀的玩家也会发现他们已经难以解决那些混乱噪杂的局面了。

短期目标：在短期时间内，你需要想办法活的更久以完成所有任务目标，而这时你的游戏能力将会慢慢逼近最后的边缘。

重复模式：玩家只要完成每个任务目标便能够打开新的任务目标。一旦你掌握了这个模式，你便可以一再地创造出游戏动力而加速前进了。

资金流量：当你完成了每个目标，你便能够获得一定量的“cooper”，而你也可以在这些“cooper”的帮助下更快地完成目标，或者打开更多新城市。在这里有个很明确的资金流量模式，即从资金来源过度到资金消费。

有限的选择：依次打开新城市后你能够打开更多城市，从而你能够不断探索到游戏中的所有内容。以前，我一直认为线性模式是一种祸害，特别是从极端角度上来看。但是，不可否认的是它也是一种工具。如果你用太多的选择困住玩家，那么关于这些选择的感知质量也会大大下降。在《蒸汽战鹰：幸存者》中，至少有4个选择。玩家可以选择打开2个城市，或者选择在更多城市中完成任务。但是不管怎样，游戏都应该明确地告诉玩家他们下一步该做些什么。

线性研究：城市地图是个很简单的一维平面图。是否我应该制作一张二维地图？可以是可以，但是我不确定这么做是否能够完善玩家所作出的各种选择。相反地，通过限制用户界面的维度，玩家可以集中于选择城市而不只是在地图上漫游，并尝试着去找寻找下一个道具的隐藏之处。

游戏总有变化。但是不管游戏系统的状态发生何种变化，都能够激励玩家继续前进。游戏中的时刻变化，或者玩家需要按压不同的按钮都能够创造出一种冲力，让玩家在掌握了一种挑战后更加有动力迈向下一次的挑战。也许玩家的起步较慢，但是随着游戏的进行，他们的速度会慢慢加快，渐渐地，他们会带着一种“流水般”游动速度朝前挺近。而“游戏之箭”也会不可避免地产生一种节奏感。这时候游戏便不再按照传统的叙述角度进行，而是更加倾向于体现游戏系统的特性。游戏节奏是指那些反复点击和拍打的声音。《蒸汽战鹰》是一款回合制战略游戏，而这也是一种典型的缓慢且节奏较为单调的游戏。然而在空中格斗的中间段，它又像是一种动作类游戏。

如果一款游戏的系统缺少明确的“游戏之箭”，那会导致游戏玩家很容易被饶进一个个死胡同中。而且游戏将难以制造出足够的反馈环路，并会导致游戏缺少主要且多样性的元素。同时游戏也需要足够的冲力感，如时间或者猛冲机制，让玩家能够在游戏中勇往直前。（本文为游戏邦/gamerboom.com编译，拒绝任何不保留版权的转载，如需转载请联系：游戏邦）

Steambirds: Survival Mobile

Daniel Cook

Today, we are launching Steambirds Survival for iOS. The layout has been rejiggered to work nicely on the iPhone. And there’s a wonderfully expansive HD version for the iPad that it easily my favorite way to play Steambirds. The Android version will follow shortly.  All of them are free, so give it a go and let me know what you think.

Though this new mobile version of Steambirds Survival shares the same name as web-based game, by partnering with Halfbrick (of Fruit Ninja fame) we’ve transformed it into a much bigger (and my opinion, better) game.

Improved progression system with new missions:  There are 64 missions, 8 of which are infinite survival modes.  If you liked Steambirds and want to play it forever, this is your game.  (Sometimes you need something a bit meatier than a tiny handful of puzzle levels.)

Free-to-play:  This is our first free-to-play game on mobile.  Like most of our games, we take the ‘free’ part pretty seriously.  I want people to buy because they love the game and can’t get enough.  I’m very curious what lessons we’ll learn.

Multiple player planes: We added a really fun recruitment system that lets you hire multiple player controlled planes.   Running through a level with three Chickadees feels amazing.  Previously lackluster planes like the Cockroach turn into fascinating exercises in multi-plane tactics.

New Reinforcement powerup: You can call in NPC allies to fight along side.   This leads to rather epic mix ups with dozens of planes pinwheeling about in a deadly dance.

Does your game have a clear “Arrow of Play”?

After launching the web version of Steambirds Survival, I was unhappy with the mission structure.  Originally there was an open list of planes that you could unlock in any order.  It seemed like a good idea at the time since ‘openness’ and ‘choice’ are good, right?  But we saw that a lot of players would cherry pick a few planes and then after they found one that they liked, they’d just play that plane to grind the in-game currency, copper. As a result, the progression lacked a clear feeling of momentum that encouraged you to trying out a wide variety of different play styles.

With the new mission structure, you unlock cities one at a time and each city reveals more cities to play.  Within each city, there are 8 sub-missions that give the player to demonstrate increasing levels of mastery to pass. Now, there’s a very clear direction to the unlocking and this should give players short term and long term goals to work towards.

In physics, Arthur Eddington coined the phrase ‘arrow of time’ to describe how time appears to flow in a single direction.  As you dabble in general relativity, you realize that time is wonderfully compressible and can be manipulated in a variety of clever ways, especially near the speed of light.  Yet even with all this variation, it consistently advances forward.

When I look at a design, I always ask “What is the arrow of play?”  This is a directional property of the mechanical systems that always moves the player forward. And like time, there’s often a surprisingly amount of variation that occurs along the way.  Some players advance slowly, others take strange side paths, but all advance.

Tools for creating the arrow of play

In Steambirds Survival, there are a variety of systems that result in a distinct arrow of play.

Inevitable decay: Plane health almost always goes downward.  There are very rare health boosts, but they are at best a temporary reprieve.

Escalation: Enemies slowly increase over time.  Waves get larger.  Difficult enemies spawn with increased frequency.  Even the best players find themselves at a point where they can’t fight back the chaos any longer and errors creep in.

Short term goals: Short term, you are trying to live long enough to complete mission goals that are just on the edge of your capabilities.

Repeated patterns: Each mission goal unlocks new mission goals.  Once you learn the pattern you can repeat it again and again building momentum like train wheels accelerating down the track.

Resource flow: Each goal you complete earns you copper, which you spend to either facilitate the completion of goals or to unlock new cities. There is a clear resource flow from sources of currency to sinks of currency.

Limited choices:  Unlocking new cities in turn lets you unlock more cities, eventually getting to the point where you have explored all the content in the game.  At once point in my career I thought linearity was a curse. And it is when taken to extremes.  But it is also a tool.   If you end up overwhelming most players with too many choices, the perceived quality of the choices provides goes down.  In Steambirds Survival, there are always at least 4 choices.  You can unlock up two cities.  Or you can attempt missions in at least two cities.  The hope is that it is clear what to do next.

Linear affordances:  The map of cities is a simple list that scrolls in along one dimension.  Should I have made a map that scrolls in two dimensions?  I could have, but I’m not sure it would have improved the quality of the choices that the player made.  Instead, by restricting the dimensionality of the UI, the player can focus on picking a city instead of wandering around a map, trying to remember which corner the next locked item is located at.   (I learned this lesson from map scrolling in Lemmings.  One of my favorite tools for simplify interfaces)

Games are about change.  The system moves from one state to another at the poking and prodding of the players. Each tick of the clock or press of a button creates momentum that leads the player on a joyful rush through challenge after mastery challenge. You start slowly.  The player builds speed and eventually they steam forward in a continuous state of flow.  The arrow of play leads inevitably to a sense of pacing.  Yet critically it approaches these not from a traditional narrative perspective, but as a property of the game systems.  The beats of the game rhythm are those clicks and taps turning tight loops over and over.  Steambirds is a turn-based strategy game, a genre typically seen as a slow and plodding.  Yet in the middle of a dog fight, it can feel like an action game.

A system that lacks a clear arrow of play results in players being mired in odd dead ends.  It isn’t enough to make a game that has feedback loops, widgets to master and all the various atomic elements of a game.  It also needs a strong sense of momentum that like time or entropy hurtles the play forward.（source:lostgarden）