Full circle rotation for both movement and aiming with independent controls for each.
EDIT: Seems like the description needs quite a bit of work. I do know that the twin-stick style of gameplay dates at least as far back as Robotron 2084 and I did play quite a few of the 90s examples, but I know barely anything about the (proto-?)genre in-between R2084 and Geometry Wars. Assistance would be appreciated.
A specific kind of control scheme often seen today in top-down and isometric indie Shoot'em Ups which has different sets of directional controls for movement and aiming. The term comes from its usual manifestation on consoles where one thumbstick steers the craft while the other aims one or more turrets. The main distinction from 'regular' dual-thumbstick controls is that the player entity's movement and aiming lines can be rotated full circle independent of each other. In truth, the control scheme itself is far older, going at least as far back as Robotron 2084. It had a strong showing in PC Shoot'em Ups of the early Nineties where in lieu of dual sticks, the directional arrows (as opposed to WASD) were used for movement and the mouse was used for turret control. Though the modern resurgence of this control scheme is arguably driven by the success of console indie titles like Geometry Wars, the PC indie scene has kept the fire burning while Webgame developers are picking it up. WASD is often used for easier access to the number keys. NOTES: As a 'genre label', the term 'Twin-stick shooter' tends to be applied to games with a Top-down or isometric camera. Games in First or Third-person perspective and side-scrollers do not receive this label even if they have similar controls. In addition,