I am currently whiteboxing levels for an iOS adventure game set in a parallel universe. The mission I am currently working on is a chase, where the protagonist is being chased through the streets of a city by the law enforcement body.

How might I be able to generate tension and vulnerability for the player whilst adhering to the limitation of our platform.

-Needs to use relatively few skeletal mesh npcs in each scene. (approx 5 - 7)
-Needs to be short (5 - 10 minutes)
-Needs to have direction (level will be linear and player must be guarded down certain paths)

Any ideas?

What kind of controls are you looking at? Perspective? Existing mechanics? Is this a "regular guy" running from "regular cops"?

Even if the design needs to be linear, you could have canned mini-cutscenes. Suppose the player runs down a street with pursuers closing down fast. While rounding a corner, the player loses control, the character ducks behind a garbage can (camera moves close), pursuers run past, character springs in the opposite direction, pursuers notice and turn back (now a little farther away) and player has control again.

Some more: it would be natural for police to chase the player with a car, which is a lot faster than the player, so it will constantly be about to reach the player, but the player can navigate so the car can't follow and must circle around buildings.

I'm doing a similar style of cutscene in a couple of areas but I was thinking more about trying to instil a bit of desperation and futility.

The pursuers are normal cops but the player does have a special power which will allow manipulation of the environment by moving objects at a distance and creating shock waves etc.

There is a section in which the police arrive in several vehicles and block the player's path.
Combat occurs with a separate camera mode which engages the enemies in hand to hand or ranged fighting.

I was thinking more about situations which would coerce the player in a particular direction. Road blocks, evasion techniques, the like. I'm trying to scale the intensity of the chase, so that it starts fairly tame with a few policemen attempting to apprehend you outside your apartment and builds until you have swat teams (story equivalents) and vehicles hounding you from multiple directions.

I was thinking of adding a timer which would count down until reinforcements arrive so the player would have to keep moving to maintain momentum.

Ideas are greatly welcome btw.

When you want the pressure to increase, you could start various obstacles across the road... fruit carts, baby strollers, grandmothers, etc. (They're all pretty standard movie cliches, but they're reused because they work.) You could time the crossings such that the player gets progressively less time to react for each one.

Also, trains and drawbridges can be useful... either as something to avoid, or to make a last-second escape.

Cool, there's a railway system which circles the city so that's a good idea. I'm wondering now if I can segment the chase by adding evasion of helicopter searchlights in several places. If the player is spotted, then troops drop down from the choppers. Viable idea?

Cool, there's a railway system which circles the city so that's a good idea. I'm wondering now if I can segment the chase by adding evasion of helicopter searchlights in several places. If the player is spotted, then troops drop down from the choppers. Viable idea?

Realistic chopper searchlights sweep very fast, and slowing them down a lot might feel jarringly unrealistic. It might be tricky to let the player take cover fast enough. The primary warning could be the sound of the chopper approaching. Then the searchlight sweep, and if it hit the player, I'd generally have it sweep over, but come right back ("hey, I think I saw something") and if the player was still in the open, that's when there would be a reaction. If player makes it into hiding, I'd have the light stay on the area for a few seconds and then move on.

Are vehicles, e.g. cars and helicopters lower cost than skeletal meshes on that platform? Most of the people shooting at you could be a fixed part of the fast moving vehicles.

As another poster indicated, car vs pedestrian creates a lot of pressure. Moving obstacles/gates would be good, e.g. a train suddenly crosses the road you're on, trapping you for a certain period of time unless you take a detour, similar with raising bridges over rivers and harbour entrances. That allows you to trap the player for an arbitrary period of time, allowing pursuers to catch up, or alternately allows the last minute getaway from the cops if they get across before the way is blocked. Non-standard means of travel give some flexibility, e.g. over a fence, down a narrow alleyway, into a drainpipe, across a zip-line, destructible terrain, interesting ways you can lose them.

In addition there's the levels of police alertness, e.g. a local chase, APB, helicopters, your face on the news.

Are vehicles, e.g. cars and helicopters lower cost than skeletal meshes on that platform? Most of the people shooting at you could be a fixed part of the fast moving vehicles.

Yes, the vehicles will have a lower cost than the skeletal meshes. I can use them for cutscenes and other animations fairly easily, however I am trying to avoid using these cinematic elements to carry the mission.

I like the idea of having your route blocked by a slow moving train whilst fighting off pursuers and waiting for an opportunity to escape. I'm currently working on a chopper search light avoidance mechanism which Stroppy katamari was kind enough to give me some hints on, but further gameplay ideas are always needed.

Well, you don't just have to use vehicles in cutscenes. You could have the search helicopter shooting at you, or police cars driving past the alley that you're hidden in, etc.

Trains do give you other options, for example stowing aboard a train or jumping on one from a bridge to get away, a chase/fight inside a train (obviously with a limited number of enemies because it is mobile), jumping off to avoid authorities waiting for you at the next station. To a lesser degree this applies to planes too.

Anything with airlock-like properties is interesting. It provides an arbitrary pause in the action, even though both parties can see each other through the window. Speaking of which, maybe areas where guns can't be used, such as near a reactor, pressurised system, explosive gas, underwater, in space, etc. Or maybe a section where they can't shoot you because you have something valuable that they need. A focus on hand-to-hand caused by this would change the nature of the chase and combat.