What does it mean when a game is referred to as a "rail shooter"? When looking at some articles about the upcoming game Rage, I saw that it had been referred to as "not a rail shooter" for console but IS a "rail shooter" for iPad/iPhone.
A rail shooter is a shooter game in which you don't have control over your movement, at least for the most part. The movement of the character is pre-determined, although some rail shooters will give you some movement control. Although this normally amounts to nothing more then choosing which path to take.
Resident Evil Umbrella Chronicles is a prime example of this:
A "rail shooter" describes a shooting game where the gameplay action runs on rails. So, much like a rollercoaster or train runs over a predefined set of tracks, so does the path of your character/vehicle in the game. How much you stick to the path can vary - for example, in Rez you can move around orthogonal to the direction that you travel on the rail. The rail's purpose is to dictate your movement through the level, while your own controlled movement is down for evasion instead. This is opposed to, say, a standard first person shooter, where you can freely move your character for both traversing the level and evading attacks.
It isn't restricted to a single track at all times, either. Continuing the Rez example, during boss fights there will be multiple segments, which can interchange depending on both time and the damage you deal. Consequently, the track you follow will vary based on which segment you're on, switching each time the phase changes. Other games include branching paths where you could follow a different part of the rails to see the level entirely differently.
When you are on 'rails' it means that you do not have control of where your character can move inside the game other than possibly moving forward and not moving forward (like a cart on rails). For example, the old arcade shooters that involve plastic guns such as Virtua Cop and Time Crisis were rail shooters.
Additionally, many non-rail shooters contain rail shooter sections. Like Half Life's 'On a Rail' level. Or in various parts of the Call of Duty series when you get a ride in the back of a jeep, truck or aircraft.