I read somewhere (or even a few places) that the dual stick genre is relatively young, and that it has exploded onto this generations downloadable services. But is it really a new genre? Where did it come from? What innovations have led us to where we are today?

Multi-directional shooter
We commonly call them dual-stick shooters today, because that is our method of controlling them on todays consoles; we use the left stick to control the movement of our avatar, and the right stick to control the direction that it shoots on a 2D plane. Once we adopt the term multi-directional shooters however, we can see that the basics of the genre have been around for many years - probably before a decent number of readers were born. The key feature that warrants this description is the ability for the players character/avatar to be moving via one control input, while being able to shoot in different directions with another input (as opposed to using one input to move, and a button to shoot in the direction you are moving).

Arcade
Dual joysticks
Robotron : 2084 was released in the arcades in 1982. Players used the left joystick to move, and the right joystick to shoot; the game had no buttons. It played very much like todays dual stick shooters, albeit limited to 8 directions of fire. Players were tasked with clearing the enemies on a single screen while attempting to save humans. Once a wave was cleared, the next wave spawned.

Brief research only turned up one more game that used the control method (if you know of any more, feel free to let me know). Smash TV was released in 1990, which played much the same as Robotron (Eugene Jarvis, the creator or Robotron, lent a hand), with higher production values, two player simultaneous play, and a basis for a story; players were contestants in a hyper violent game show. Once in an arena, enemies poured through doors until the area was cleared, and at times players were allowed to choose which arena they wanted to play next as they made their way to the bosses.

Rotary joysticks
Ikari Warriors, released in 1986, was the first arcade game to introduce rotary joysticks. Whereas the dual joystick shooters fired as soon as you pushed them in a direction, Ikari Warriors sported only one joystick and a shoot button. As well as the joystick having 8 directional movement to control the players movement, it was shrouded in a knob that could also be turned with 8 degrees of movement.

This method may seem slightly inferior to dual joysticks; you still have to aim and them press the shoot button. Having not played Ikari Warriors myself, I don't know how this affected gameplay. I did however play Heavy Barrel (1987) and Midnight Resistance (1990) at the arcades. These games used the same rotary joystick, but also had limited ammunition for upgraded weapons. In my experience, this gameplay mechanic was better served by rotary joysticks than continually tapping a second joystick in a direction to conserve ammo.

Rotary Dial
Tron introduced the rotary dial to arcades in 1982. It had a joystick for moving, a button for firing, and a rotary dial to control the direction of fire during certain modes. Forgotten Worlds is another arcade game that used the rotary dial, which was also a button. It could be turned, but required you to push down on the dial to actually fire. I could not find information on how many degrees of fire these allowed, but footage of the games would indicate more than 8 directions.

Consoles
There were console ports for many of the above listed games at or near the time of their arcade release. Due to the limitations of the controllers at the time, some of them lost the seperation between movement and firing; players could only shoot in the direction they were travelling. Smash TV for the SNES was perhaps the most faithfully ported game of those listed above. It allowed for movement with the D-Pad, and the face buttons to determine direction of shooting (pressing 2 adjacent buttons to fire diagonally). The same method is available in the XBLA version, as it is a port and not a remake that takes advantage of the controllers dual analog sticks. Robotron 2084, the game to start it all, is also available on XBLA, but it too has only had a facelift, no changes to the original controls.

As I recall, the Forgotten Worlds port on the Master System did away with a fire button altogether, had you firing at all times, and the two buttons rotated your character clockwise or counterclockwise. While this had the minor effect of slowing down how fast you could turn, it did give you more than 8 degrees of fire.

Personal Computers
Personal Computers have had the controls available since day 1 for multi-directional shooters; 4 keys for movement and 4 keys for fire direction (holding two for diagonals). This limits it at 8 directions (unless you want to assign a cumbersome number of keys), but has been possible for decades. I'm sure it has been done, but I don't specifically recall any games that adopted this method.

The mouse has been much more effective at giving more degrees of fire. This is a little different than aiming in a general direction and firing, but the in-game effect is similar enough to bear mentioning. The first game I recall to use this method was Abuse, released in 1996. The keyboard moved your character, while the mouse was used to aim where you wanted to fire, and left mouse button fired your active weapon. I don't recall the control scheme becoming a raging hit, but I have seen it used since in some flash games (Unreal Tournament flash, for example).

A similar system to this has been adopted this generation by Nintendo systems, the DS and the Wii, using the stylus and pointing the remote instead of using a mouse, in the likes of Monster House for the DS, and Geometry Wars Galaxies for both systems.

Why suddenly so popular?
Given that the first dual stick shooter was released in arcades in 1982, why does it seem like it has taken until this generation of consoles for it to really take off and have more than a few dozen titles in under 3 years? The first thing I pondered was whether it was due to the limited degrees of fire, which are possible with todays analog sticks. But if it was only that limitation, we would have seen a proliferation of arcade games if the demand was there; I don't see any reason why Geometry Wars could not have existed in an arcade cabinet over 10 years ago. Even in the home, I don't recall any such games for the Playstation 2, which introduced dual analog sticks as standard. If there were, they certainly weren't heralded like those that belong to this generation.

Is it other in-game technology? I don't think so. Apart from prettier graphics, I don't see how any of todays dual-stick shooters could not have been made for the Playstation 2. I don't know much about what happens under the hood, but I'm sure the PS2 could have handled Geometry Wars simple shapes; potentially the large number of enemies might have taxed the system, but generally the gameplay could have remained intact. The newest thing added this generation is leaderboards. That however is not universal to the appeal of all these titles, and I doubt it was the one factor that pushed them in the stratosphere.

Which brings us to price, the only other item I see as being a potential factor. People obviously DO want to play these games, otherwise we wouldn't see sequels like Geometry Wars 2 or Assault Heroes 2, and the plethora of other dual stick shooters that grace todays consoles, and continue to sell. However, the vast majority of them are downloadable games that cost US$10/AUS$15 or less. The only retail games of this nature I recall this generation are the previously mentioned Monster House and Geometry Wars Galaxies. Monster House may have sold more copies based on its licence (and it's actually a decent game) and Geometry Wars Galaxies probably got a boost by awareness of the previous game. However all of those games sold less than 100,000 units (according to http://www.vgchartz.com/), and I imagine without the licence or brand awareness, they would have performed worse.

But do I have it right? Or is there another factor? Some perfect storm? Perhaps with Geometry Wars being a launch title for XBLA and so cheap, people purchased it to test this newfangled downloadable service and became hooked by the gameplay. Perhaps the combination of its initial sales, critical acclaim, and use of leaderboards had people talking about the game and brought the genre to the forefront? Or perhaps ease of distribution made developers more interested in attempting their own take on such a simple (yet enjoyable) concept, making the genre more well known simply by weight of numbers?

In any case, the basic tenets of the genre have been around for over 25 years, so it is certainly not a new genre. That said, I still think it is an underdeveloped one when compared to other genres like fighters, platformers and first person shooters which have had hundreds of games developed for them. I look forward to seeing what the gaming community can come up with in the future; while the basic controls will remain the same, I see plenty of room to lay varied and interesting gameplay concepts on top of them. Are there any particular innovations you would like to see?

Disclaimer : I'm no video game encyclopaedia or historian; I don't think I've ever seen a Robotron 2084 or Tron cabinet, let alone played one. While I did some research I may have missed some other relevant games or information; let me know about them, and I will edit them in.

Sources : Information and images mainly obtained from individual game pages on wikipedia and www.klov.com (Killer List of Video Games).