Real-time strategy (RTS) games are a genre of computer wargames which do not progress incrementally in turns. Brett Sperry is credited with coining the term to market Dune II.

In an RTS, as in other wargames, the participants position and maneuver units and structures under their control to secure areas of the map and/or destroy their opponents‘ assets. In a typical RTS it is possible to create additional units and structures during the course of a game. This is generally limited by a requirement to expend accumulated resources. These resources are in turn garnered by controlling special points on the map and/or possessing certain types of units and structures devoted to this purpose. More specifically, the typical game of the RTS genre features resource gathering, base building, in-game technological development and indirect control of units.

The tasks a player must perform to succeed at an RTS can be very demanding, and complex user interfaces have evolved to cope with the challenge. Some features have been borrowed from desktop environments, most prominently the technique of „clicking and dragging“ to select all units under a given area.

Though some game genres share conceptual and gameplay similarities with the RTS template, recognized genres are generally not subsumed as RTS games. For instance, city-building games, construction and management simulations, and games of the real-time tactics variety are generally not considered to be „real-time strategy“.

Refinement and transition to 3D

The real-time strategy genre has been relatively stable since 1995 and additions to the genre’s concept in newer games tend to be introducing more units, larger maps, terrain and similar, rather than innovations to the game concept with new games generally focus on refining aspects of successful predecessors. As the paragon example of gameplay refinement, Cavedog Entertainment’s acclaimed Total Annihilation from 1997 distilled the core mechanics of Command & Conquer, and introduced the first 3D units and terrain in real-time strategy games. In 1997, Ensemble Studios tried to combine elements of Civilization with the real-time strategy concept in Age of Empires by introducing ages of technologies. This combination was refined further by Stainless Steel Studios‘ Empire Earth in 2001. GSC Gameworld’s Cossacks: European Wars series took the genre in a different direction, bringing population caps into the tens of thousands.

Populous: The Beginning (1998) and Homeworld (1999) were the first completely 3D real-time strategy titles. Homeworld was notable in that it featured a 3d environment in space, therefore allowing movement in every direction, a feature which its semi-sequel, Homeworld Cataclysm (2000) continued to build upon adding features such as waypoints. Homeworld 2, released in 2003, streamlined movement in the 360° 3D environment. Furthermore, Machines, which was also released in 1999 and featured a nearly 100% 3D environment, attempted to combine the RTS genre with FPS although it was not a particularly successful title. These games were followed by a short period of interest in experimental strategy games such as Allegiance (2000).

It is only in approximately 2002 that 3D real-time strategy became the standard, with both Warcraft III and Ensemble Studio’s Age of Empires III (2005) being built on a full 3D game engine. Kohan: Immortal Sovereigns introduced classic wargame elements, such as supply lines to the genre. Battle Realms (2001) was another full 3D game, but had limited camera views.
The move from 2D to 3D has been criticized in some cases. Issues with controlling the camera and placement of objects have been cited as problems.

Relatively few genres have emerged from or in competition with real-time strategy games, although Real-time tactics, a superficially similar genre, emerged around 1995. In 1998, Activision attempted to combine the real-time strategy and first-person shooter genres in Battlezone, while in 2002 Rage Games Limited attempted this with the Hostile Waters games, and Natural Selection, a game modification based on the Half-Life engine.

Specialization and evolution

A few games have experimented with diversifying map design, which continues to be largely two-dimensional even in 3D engines. Earth 2150 allowed units to tunnel underground, effectively creating a dual-layer map; three-layer (orbit-surface-underground) maps were introduced in Metal Fatigue. In addition, units could even be transported to entirely separate maps, with each map having its own window in the user interface. Three Kingdoms: Fate of the Dragon (2001) offered a simpler model: the main map contains locations that expand into their own maps. In these examples, however, gameplay was essentially identical regardless of the map layer in question. Dragonshard (2005) emphasized its dual-layer maps by placing one of the game’s two main resources in each map, making exploration and control of both maps fundamentally valuable.

Some games, borrowing from the real-time tactics (RTT) template, have moved toward an increased focus on tactics and a de-emphasis on resource management, with titles such as Warhammer 40,000: Dawn of War (2004), Star Wars: Empire at War (2006), and Company of Heroes (2006) replacing the traditional resource gathering model, where designated resource gathering units collect the resources used for producing further units or buildings, with a strategic control-point system, where control over strategic points progressively yields construction/reinforcement points. Ground Control was the first such game to replace individual units with „squads“.

Others are moving away from the traditional real-time strategy game model with the addition of other genre elements. An example is Sins of a Solar Empire, released by Ironclad Games, which mixes elements of grand-scale stellar empire building games like Master of Orion with real-time strategy elements.

Gameplay

In a typical real-time strategy game, the screen is divided into a map area displaying the game world and terrain, units, and buildings, and an interface overlay containing command and production controls and often a „radar“ or „minimap“ overview of the entire map. The player is usually given an isometric perspective of the world, or a free-roaming camera from an aerial viewpoint for modern 3D games. The primary form of input is the mouse which is generally accompanied by keyboard shortcuts, with which commands are given and the map is scrolled. Gameplay generally consists of the player being positioned in the map with a minimal production base capable of creating the basic units and buildings that are needed to start playing. Later, players progress to eventually create increasingly powerful units and buildings, or a small force, the core of which is generally a unit capable of establishing the initial production base. Thereafter, the game is typically a race of resource gathering, technology research and unit production to claim territory and suppress and defeat the opposition through force or attrition.

Tactics vs. strategy

Though strategy and tactics in military terminology refer to long- and short term military objectives, usage in strategy wargames generally diverges from dictionary definitions and identifies the terms with base- and economic versus combat management. Taking this into consideration, real-time strategy games have been criticized for an over-abundance of immediate and minute (in this context referred to as „tactical“) considerations when compared to the amount of strategic gameplay found in such games. For instance Chris Taylor, lead designer of Supreme Commander, apparently unaware of the real-time tactics genre, argued, using conventional meanings of the terms, „that although we call this genre ‚Real-Time Strategy,‘ it should have been called ‚Real-Time Tactics‘ with a dash of strategy thrown in.“ Taylor then posits his game as surpassing this mold by including additional elements of broader strategic scope. Curiously, real-time strategy games have also been criticized for their lack of combat tactics. In this case, real-time tactical games have been suggested as a suitable substitute.

Graphics

Total Annihilation (1997) was the first real-time strategy game to utilize true 3D units, terrain, and physics in both rendering and in game-play. For instance, missiles in Total Annihilation travel in real-time in simulated 3D space, and can miss their target by passing over or under it. Similarly, missile-armed units in Earth 2150 are at a serious disadvantage when the opponent is on high ground, as the missiles often hit the cliffside, even in the case when the attacker is a missile-armed helicopter. Homeworld and Warzone 2100 (both released in 1999) advanced the use of fully 3D environments in real-time strategy titles. In the case of Homeworld, the game is set in space, offering a uniquely exploitable 3D environment in which all units can move vertically in addition to the horizontal plane. However, the near-industry-wide switch to full 3D was very gradual and most real-time strategy titles, including the first sequels to Command & Conquer, initially used isometric 3D graphics made by pre-rendered 3D tiles. Only in later years did these games begin to use true 3D graphics and game-play, making it possible to rotate the view of the battlefield in real-time.

Recently, real-time strategy games have more commonly incorporated physics engines, such as Havok, in order to increase realism experienced in gameplay. A modern real-time strategy game that uses a physics engine is Ensemble Studios‘ Age of Empires III, released on October 18, 2005, which used the Havok Game Dynamics SDK to power its real-time physics. Company of Heroes, released on September 14, 2006, is another real-time strategy game that uses real-time physics as a part of gameplay, including fully-destructible environments as well.

Sources: Wikipedia Modified by Fanterazzi