TimeSplitters 4/Game Rules

## Element Properties

Props must have the physical properties of mass, friction, and damage to inform their behaviour. These properties may change when the prop interacts with the 6 “elements” present within the game. They will not need to react to all elements, but, the more reactions they have, the better. The elements are:

* **Fire** - Burns flammable props, reducing their mass and, after their fire damage quotient is exceeded, changes them to a burnt state and ultimately destroys them. Turned to steam by water, turns acid into gas.
* **Water** - Reduces friction somewhat, increases the length of exposure to fire before ignition, extinguishes fire, can increase mass somewhat for certain props. Turned to steam by fire, conducts electricity across the prop, turned to acid by gas.
* **Steam** - Becomes water on props, slows fire damage for certain props.
* **Ice** - Freezes props, reducing their friction to almost zero, increases length of exposure to fire before ignition, reduces resistance to explosives/force, increases mass a little. Turned to water by fire.
* **Electricity** - Explodes electrical props, massively speeds up mechanical props, can jump between conductive materials, makes hair stand on end, makes characters strobe-dance whilst flashing white with their skeleton revealed in black, causes hats and wigs to catch fire, can apply sudden force to characters sending them flying with sufficient voltage, slows fire damage for certain props, will eventually cause zombies to catch fire.
* **Acid** – Dissolves certain props, reducing their mass and, after their acid damage quotient is exceeded, changes them to a dissolved state and ultimately destroys them. Turned to gas by fire.
* **Gas** – Only affects living characters. Turned to acid by water.
* **Explosion/physical force** – Damages props and applies force which can propel them if it overcomes mass and friction; if the damage exceeds the prop’s damage quotient, it changes to a smashed state, characters killed by explosives leave smoking boots.
* **Magnetism** – Disorients Robots, causes metal objects to stick to robots, can cause rockets to return to sender…

## Pickups

* **Small Objects** – Small props can be picked up and used as a melee weapon or thrown. Examples are detached zombie limbs and chemical flasks. When near an appropriate object, a symbol of it will appear in the HUD. You will be prompted to press a button to pick it up.
	+ **Option 1** – Throwing Items are carried in the left hand, two handed guns are held 1-handed for the duration. Items can be thrown, a quick press throws maximum distance, holding the button builds up a power bar to judge the throw. Items can also be dropped on a separate button. If a melee item such as a baseball bat or limb is chosen to be picked up by the player, it replaces the gun in the right hand. It will be held until a gun is selected, at which point it is dropped or another melee item is picked up where again it is dropped. Finally, it may be thrown or it may break. If a melee weapon and a throwable object are both held, the throw button throws the object first, retaining the melee weapon. If a new gun is picked up by running over it while holding a melee weapon, the gun goes into the inventory. It is not selected and so the melee weapon is not dropped.
	+ **Option 2** – Throwing items and melee items replace the weapon. It is impossible to shoot whilst carrying one. Selecting a gun drops the item. It is only possible to hold 1 item at a time.

## Physics Objects

All props are physics objects. This is fine when they are spread out, but, if they are gathered together, the CPU hit becomes too great. In this situation, props will have to be removed in some way, for example dissolving. All prop types will have a priority to indicate the order in which they will be removed. Props with the same priority will be removed according to first visibility, then length of time they have been inactive.

## Critical Props

A critical prop would be the Bag in Capture the Bag. If it is thrown somewhere inaccessible, we need to be able to handle this behaviour. Methods would be to respawn the bag if it is inactive for a certain period of time, or to use comedy physics to scoot it back into play.

## Melee

There are three types of melee attack – with a melee weapon such as a chainsaw, with a gun or an unarmed attack such as a punch. Melee weapons do the most damage, followed by gun melee and, finally, punches. The exception is the Timesplitter unarmed melee attack, which can be very powerful. When a melee attack is initiated, we see whether there is a target both within a narrow cone projected from the front of the player and within range. If both conditions are met, the melee attack will be successful and we can play appropriate animations to show the attack connecting with the enemy’s head, coupled with a hit react. It is important to give the feedback of a successful hit through animation and sound. An attack from the rear is more damaging than an attack from the front.

## Doors

In all game levels, all doors slide either sideways or upwards regardless of time period. No swing doors, they are a pain in the arse. (Hotel is an exception as it is not playable)

## Cloak

Splitters or humans with an appropriate powerup can cloak. This may be indefinite or have a time component. TimeSplitters can only attack when decloaked. Cloaked characters are not completely invisible, but they are hard to see except from certain circumstances. Particle clouds reveal the passage of cloaked characters, as do pools of liquid. Sonar vision mode also reveals them.

## Weapon Pickups

Humans, zombies and certain robots can pick up new weapons by running over them. If the weapon is not currently possessed, it will be picked up. There are various player-selected options for what happens next. Players can choose to always switch to the new weapon picked up, to never switch, or to switch if the weapon is better than the one currently wielded. The player can, in his profile, rank all the weapons in order so that they choose themselves which weapons are better than others, else we use the default rankings. If a weapon is already possessed, then running over it adds ammo for the weapon. A weapon that is in the player's inventory and then run over never causes the weapon to switch. When a gun runs out of ammo, it is dropped.