The following was published in the June/July 2008 issue of Game Developer magazine…

The industry’s first video games – Pong, Asteroids, Space Invaders – were all 2D by necessity. A few early games experimented with basic 3D, such as Battlezone‘s vector-based tank simulator, but these games were simply interesting footnotes, not the mainstream. Everything changed in 1992 with id Software’s Wolfenstein 3D, which popularized 3D as the leading edge of game development. Since then, almost no corner of the industry has been left untouched by the transition from 2D to 3D graphics. Almost every franchise, from Mario to Zelda to even Pac-Man himself, has tried out 3D technology.

Now that this transition is essentially complete, it may finally be a good time to ask ourselves what we have learned in the process. What are the advantages of 3D? What are its challenges? For what is 2D still best? Perhaps game developers can now at last choose the best graphics environment on a game-by-game basis instead of making the move to 3D just from competitive pressure.

Troubles with Cameras

3D games and cameras have a long, troubled history. While first-person games are essentially a solved problem for 3D, most other genres are still adapting to the new technology. Teaching the player how to use a camera while also teaching the game’s core experience can be a tough challenge. One distinct advantage 2D games have is that easiest camera to teach is one which doesn’t exist. In fact, 3D game have been trending away from giving the player extensive camera controls.

Super Mario 64 is credited with being the first successful 3D platformer, but it required the player to make extensive use of the camera controls to keep Mario visible and heading in the right direction. Platformers attempted more intelligent camera systems over the years, trying to dynamically determine the best perspective at any given time. Such solutions, however, are bound to fail at some point, such as when the character gets stuck behind a corner or under a ledge. To solve this sticky problem, Prince of Persia: The Sands of Time introduced two alternative static camera perspectives that the player could access at any time. God of War took this approach a step further and enforced a single fixed camera for each of the game’s scenes, approaching the level design almost like a film cinematographer. Super Mario Galaxy has a dynamic camera without any controls whatsoever although it adopts a nearly top-down view to enable the player to always see the surrounding area. Other avatar-based games, such as World of Warcraft, prevent the player from tweaking the camera while moving, ensuring that the player can never end up running directly into the camera.

Strategy games have also gone through a progression of camera systems, similarly trending towards taking camera controls away from the player, or at least hiding them from the novice. Star Wars: Force Commander, one of the first 3D RTS games, had an infamously difficult free camera, which made finding the right angle to view your troops a constant chore. Warcraft 3 may be considered the first RTS to get 3D right. The designers achieved this feat by greatly restricting the camera’s freedom – the zoom range was minuscule, the pitch angle came directly from zoom, and the only camera rotation was attached to an obscure hot-key. Lead Designer Rob Pardo describes the process behind these restrictions:

With 3D, we decided to bring the camera down quite a bit and try out some things. The problem was with the camera pulled all the way down, it became a pseudo-third-person experience. It was disorienting when you went around the map, and it was difficult to select units in battle because your camera frustum was pointed in one direction so you didn’t have a good view of the battlefield. It was a challenge because we still wanted a fun strategy game. Eventually we pulled the camera into a more traditional isometric view, and that’s when we really started making progress.

But Which 2D?

Not all 2D games are the same. Two major styles have developed: “classic” 2D, which is a straight top-down (chess/checkers) or side-on (Sonic games) view, or isometric 2D, which tries to fake 3D with an isometric projection at a pre-set angle. Before making the full jump to 3D, many genres made a move from classic 2D to isometric 2D as an intermediary step. For example, the original Civilization had a traditional top-down grid view while Civ 2 had a three-quarters isometric view. While this new perspective gave the game world a more life-like appearance, the change did come at a cost to the user’s game experience. Namely, distances are much more difficult to judge on an isometric grid as the east-west axis takes up twice as many pixels as the north-south axis. To solve this problem, for Civ 4, our 3D perspective actually hearkened back to the original game as we showed the game’s grid straight ahead and not at an angle. The easier the players perceive the grid through the graphics, the better they can “see” their possible decisions.

It is significant that Advance Wars: Days of Ruin (DS), the latest version in this long-running series, has maintained the traditional chess-board view, keeping the player focused squarely on the core gameplay. The “chunky” unit art familiar to the series is a great example of an artistic style which flows from the limitations of the game’s presentation. In contrast, a game heavily influenced by the Advance Wars series – Age of Empires: The Age of Kings (DS) – chose to move the same game mechanics into an isometric 2D world. The transition was not altogether successful. Not only was the immediacy of the grid harder to follow, but because units extended beyond the edges of their tiles, selecting units and locations became a significant problem when groups of units overlapped one another. Thus, tile-based games tend to be more successful when a top-down view is adopted.

Graphics are not Gameplay

3D graphics are not the same things as 3D gameplay. For example, two sci-fi RTS games – Homeworld and Sins of a Solar Empire – use very similar 3D engines to recreate the vast scale and special effects of deep space combat. However, they do not share core gameplay as Homeworld is a “true” 3D game, meaning that ships could be moved freely along the z-axis, while Sins actually has 2D gameplay as the game is played on a single, flat plane, meaning that ships cannot fly above or below each other. In fact, the game could have been implemented with a 2D engine; using 3D was a secondary choice to enable smooth zooming and to evoke the “feel” of outer space. The team’s decision to adopt 2D gameplay saved Sins from the interface complications of Homeworld, which required two or three separate clicks to give units a destination in all three dimensions.

Many other example of hybrids exist, where games use 3D graphics to render essentially flat 2D gameplay. Super Smash Bros. Brawl, for example, is fought on a single, vertical plane that uses the 3D engine for the all-important animations and fluid background environments. Cliff Bleszinski has described the gameplay of Gear of War as a horizontal version of the classic 2D platform Bionic Commando. Instead of using the grappling hook to ascend from platform to platform, Gears players “jump” from cover point to cover point along a horizontal plane.

Essentially, most games can be divided into three play mechanic categories which are related to but semi-independent from the graphics:

* Tile-Based Games (Tetris, Puzzle Quest, Civilization, Oasis, NetHack)
* Single-Plane Games (Starcraft, Madden, Geometry Wars, Super Mario Bros.)
* Real-World Games (Portal, Super Mario Galaxy, Burnout, Boom Blox)

Good rules-of-thumb exist for each of these categories. Real-world games essentially require 3D graphics. Of course, the term “real” is not meant to be taken literally. The gun from Portal is not real, but the user enjoys playing with it because of the expectation that its unique behavior exists in harmony with the physics and gravity of our own world. The easiest way to guarantee that the player bring along assumptions from the real world is to immerse them in a 3D environment that looks, behaves, and feels real. These environments are the equivalent of what-you-see-is-what-you-get for games.

On the other hand, tile-based games usually work best as top-down 2D games, with little separating the player from the core game mechanics. For single-plane games, the choice comes down to largely one of aesthetics and technology. Can the game’s platform support 3D graphics smoothly? Does 3D provide an advantage, from either shared animations or dynamic effects or general flexibility, that makes the technology worthwhile?

All in all, 2D is an underrated style that is often unfairly ignored as an old technology. Developers should not underestimate the advantages of avoiding the technical overhead of maintaining a bulky 3D engine and asset pipeline. Furthermore, well-made 2D graphics never really go obsolete. Sulka Haro, lead designer of Habbo Hotel, likes to point out that their retro 2D style looks just as good today as when the game launched eight years ago. If they had used 3D, Habbo would probably be on its second or third engine by now. Once a 2D engine is up and running, the artists can focus on simply improving the game’s look piece by piece. If 2D helps clarify and communicate the underlying game mechanic, then all the better.

The following was published in the April 2008 issue of Game Developer magazine…

Amongst computer games, the strategy genre is one of the oldest and proudest, with a strong tradition, running from M.U.L.E. to Civilization to Starcraft and beyond. Nonetheless, certain design mistakes keep being made over and over again. Here are seven of the most common:

1. Too much scripting

Strategy games have a direct lineage from board games, and the fun of playing the latter comes from understanding the rules and mechanics of the game world and then making decisions that have consequence within that world. Computerized strategy games allow a single player to experience this same world on his or her own. At some point, however, strategy developers began to create lengthy, scripted scenarios as the single-player portion of their games. (In fact, the recent World in Conflict shipped without a single-player skirmish mode altogether.) These scenarios have a peculiar feeling – they use some of the same rules as the core game while often violating others. The AI takes action depending not on its own development rate or strategic priorities but on whether the human has hit certain triggers. In many scenarios, in fact, the human cannot even lose because – when defeat approaches – the script will freeze the AI and starting pumping in free units for the player. Further, these scenarios are often built around specific “objectives” to achieve, such as destroying a specific structure or capturing a single point. This artificial environment takes decision-making away from the player. Not only is there only one path to victory, but the player’s performance along that path may not even matter. Games without interesting decisions get boring quickly. Fortunately, some recent strategy games, such as Sins of a Solar Empire and Armageddon Empires, have returned to open-world, random-map gameplay – without pre-set objectives or artificial triggers – and are reminding us of the joy of cohesive and consistent strategy games.

2. Too much stuff

The temptation to pile extra units and buildings and whatnot onto to an already complete design is strong. Indeed, I have seen many developers describe games as simply a collection of stuff (“18 Weapons! 68 Monsters! 29 Levels!”) This approach is wrong-headed. A game design is a collection of interesting decisions, and the “stuff” in the game is there not just to fill space but to let you execute decisions. Games can provide too few options for the player but – more commonly – games provide too many. How many is just right? Obviously, there is no magic number, but it is possible to come up with a good rule-of-thumb for how many different options a player can keep in his or her mind before everything turns to mush. Blizzard uses the number 12 to make sure their RTS’s don’t get too complex. StarCraft averaged 12 units per side. So did WarCraft 3 (not counting Heroes). And you can bet that StarCraft 2 is going to be in that neighborhood as well. In fact, Blizzard has already announced that, for the sequel, they will be removing some of the old units to make room for the new ones. Players must be able to mentally track their in-game options at one time, and putting too many choices on the table makes it impossible to understand the possibility space.

3. Limited play variety

No matter how good your game, it is going to get stale after awhile. It’s unfortunate when a great game doesn’t take the few steps necessary so that players can change the settings to create alternate play experiences. Company of Heroes is an incredible tactical RTS, a watershed moment for the genre – but the game allows neither Axis vs. Axis battles nor matches with more than two teams. This design choice may fit the fiction of WWII, but it significantly reduced the game’s play variety. An example of an RTS that got this right is the Age of Empires series. Not only could you mix-and-match any combination of civilizations and players and teams, but you could also design your own map scripts. I remember one interesting Age of Kings map that had almost no wood but tons of stone and gold, which turned the game’s economy upside-down. The game even allowed multiple players to control the same single civilization (one could control the military, the other the economy, for example). Thus, I’ve played 2-vs-3 games of AoK where the sides with 2 civs was actually controlled by 4 players (and, in fact, handily won the game!) These simple variations probably doubled the life-span of AoK amongst my group of friends. Significantly, these options should be orthogonal to the game’s core mechanics – they need to add variety without adding complexity.

4. Black box mechanics

Sometime during the late-90’s, around when Black & White was being developed, the concept of an interface-less game came into vogue. The idea was that interfaces were holding games back from larger, more mainstream audiences. Ever since then, I have noticed a discernible trend to hide game mechanics from the player. Age of Kings shipped in 1999 with an incredible reference card listing every cost, value, and modifier in the game. For modern RTS’s, however, it’s unusual if the manual actually contains numbers. I want to emphasize that the answer here is not to bathe the players in complicated mathematics in the name of transparency. Instead, designers should think of their interfaces as having two levels: a teaching level and a reference level. The teaching level focuses on first-time players who need to know the basics, like how to build a tank and go kill the bad guys. The reference level should answer any question the player can think of about how a game mechanic works. It is perfectly fine, by the way, to put this info inside of a separate in-game resource, like the Civilopedia. Rise of Legends implemented an interesting version of this two-interfaces idea. Most of the popup help in the game had an “advanced” mode that you could unlock by holding down a key, giving you significantly more details about the game’s underlying mechanics.

5. Locked code/data

Protecting your code and data is a very natural instinct – after all, you may have spent years working on the project, developing unique features, pushing the boundaries of the genre. Giving away the innards of your game is a hard step for many developers, especially executives, to take. Nonetheless, we released the game/AI source code for Civ 4 shortly after shipping, and – so far – the results have been fantastic. Three fan-made mods were included in the game’s second expansion pack – Derek Paxton’s Fall from Heaven: Age of Ice, Gabriele Trovato’s Rhye’s and Fall of Civilization, and Dale Kent’s WWII: The Road to War – and so far, these scenarios have been heralded as one of Beyond the Sword’s strongest features. These mods would have been nowhere near as deep or compelling (or even possible) if we had not released our source code. For many PC developers, I’m preaching to the choir, so I’d like to be very clear that the problem is worst amongst strategy games. For whatever reason (perhaps the lack of a pioneering developer like id Software?), strategy developers have been much more closed off to modding than their shooter and RPG brethren. There are exceptions, like Blizzard’s fantastic scenario editor for WarCraft 3, but by and large, strategy modders do not have many places to turn for platforms on which to work, which was one reason we felt compelled to focus on modding for Civ 4. Giving stuff away can feel good. It should also feel smart.

6. Anti-piracy paranoia

The damage that piracy does to our industry is impossible to calculate but also impossible to ignore. Few company heads can be as brave as Stardock’s Brad Wardell, who chose to leave out copy protection altogether for the Galactic Civilization series. (They encourage paying customers by providing on-line updates to players with legitimate serial numbers.) Having some sort of mechanism to stop casual piracy is a given in the industry, but what is not a given is the hoops companies will make their customers jump through just to be able to start the game. The most important question to ask is “will this added security layer actually increase our sales?” A good place to be lenient, for example, is with local multi-player games – in other words, can players without the CD join a multi-player game hosted by a legitimate copy. Starcraft let you “spawn” extra copies of the game that could only join local multi-player games. Allowing unlimited LAN play was our unofficial policy for Civ 4 as well. The game does a disk check when opening the executable but not when you actually launch the game; thus, a group of 4 friends could just pass one disk around for local multiplayer games. We do not believe players are willing to buy extra discs just for LAN parties, which are rare events. However, we would love for new players to be introduced to Civ in these environments, encouraged by their friends who are already fans. At some point, they are going to want to try single-player – in which case, it is time for a trip down to the local retailer to buy their own copy.

7. Putting story in the wrong places

Story and games have a checkered history. Too many have suffered from boring cut-scenes, stereotyped characters, and plots that take control away from the player. Especially problematic are games which don’t let the player fast-forwarding through cringe-worthy dialogue. The worst offense, however, is when a story gets stuck somewhere it really doesn’t belong. Like in a strategy game. After all, strategy games are the original games. Humans first discovered gameplay with backgammon and chess and go; it’s a noble tradition. The “story” in a strategy game is the game itself. Picking a specific example, how much better of a game would Rise of Legends have been if Big Huge Games had given up on creating a story-based campaign and instead iterated on the excellent turn-based Conquer the World strategy layer from Rise of Nations? Ironically, the campaign mode was my favorite way to play RoL. I loved that you could only acquire technologies and advanced units on the strategic map between missions, which helped simplify the core RTS game. However, I enjoyed the campaign in spite of the story, not because of it. The key point here is that, for the sake of chasing a story, Big Huge Games missed a big opportunity to match a great core RTS game with a simple, overarching strategy layer that could be infinitely replayable. They are not alone; almost every other RTS developer seems to be falling into the same trap, and it is time for this trend to stop.