Difference between revisions of "Spaceship Shenanigans"

Revision as of 19:07, 2 September 2007

Summary

This game resembles the arcade game Missile Command, and tests distribution and shifting of attention, and the effect of multimodal (auditory and visual) stimuli. The player defends a base at the bottom centre of the display, by sweeping a weapons turret left (left arrow) or right (right arrow) along a semicircular defence perimeter. Friendly ships and hostile missiles warp into the space outside this defence perimeter, at a random distance from it, then move towards the perimeter. 1/3 of the sessions contain friendly ships (distractors), whilst in the other 2/3 the only contacts are hostile missiles.

Missiles that detonate against the perimeter weaken it, increasing the base's vulnerability to attack and decreasing the player's energy resources. The turret fires automatically at any missile in the sector of space currently covered by it -- but the turret can cover only one sector at a time. In distractor sessions, friendlies materialise at random intervals between 0 and 800 ms of each other, temporally interspersed with the missiles. Although at most one missile is incoming at any given time, 0 to 800 ms (uniformly distributed) after that missile detonates or is destroyed, another materialises in a randomly selected location within a different sector. Reaction time within this paradigm measures the player's ability to distribute attention across a broad field in the presence or absence of distractors.

In 1/2 of the non-distractor sessions ( 1/3 of the total number of sessions), all missiles materialise right at the defence perimeter, and an early-warning system displays a large, 10 hz (50% duty cycle) flashing arrow at the bottom centre of the display, in the middle of the player's base. The arrow appears either 100 ms (one flash) or 800 ms (eight flashes) prior to the materialisation of the missile, and remains until the missle materialises. The player then has until 800 ms after the missile materialises before it arms itself and detonates. However, the early-warning system is fallible, and in some cases (20%), it indicates a sector 90º away from the missile's actual sector. In addition, in half of the trials the arrow is accompanied by a klaxon (100 hz square wave modulated at 10 hz in synchrony with the arrow), and in the other half there is no klaxon. This aspect of the task combines a centrally cued Posner attention paradigm (testing effects of cue validity and cue-target onset asynchrony) (Posner et al. 1987) with a test of multimodal cueing advantage (visual only or visual and auditory).

In a bonus stage at the end of each “Turret Command” session, missiles materialise only in the centre sector, and always at a highlighted target location at a constant distance from the defence perimeter. Friendly ships appear in the other sectors, horizontally displaced from the target location. The turret is in manual firing mode, and the only task -- an easy one -- is to fire (space bar) to destroy each incoming missile, whilst ignoring the friendly (probe) stimuli. This aspect of the task allows physiological measurement (via amplitude of the P1 event-related potential) of the spatial distribution of attention, and also provides a focused-attention comparison for the distributed-attention conditions.

KNOWN BUGS

This mini-game is not yet implemented.

Premise

The WSS White Giant is under attack! It is your job as Tactical Officer to guide the defense system to aid your fighters in shooting down incoming squadrons of enemy fighters and destroyers. Then jump in the hot seat of a C-24 fighter and travel with a fighter group to counterattack the enemy carrier launching the attacks on the White Giant.

Objective

Protect the WSS White Giant and destroy all enemy carriers.

Characters

Cheetah C-24 Fighter: See Meteor Madness

WSS White Giant: One of WSI's Constellation class carriers. It can launch C-24s, shoot EMP pulses that stun enemy ships and damage their shielding. It is also equipped with the Close-in Antiship Turret (CAT) which automatically attacks enemy ships that get close enough.

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Wasp Fighters: Launched from enemy motherships. They attack WSI ships in waves.

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Mantis Destroyer: A medium-sized enemy ship. Attacks the player's carrier in small attack groups.

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OoO Mothership: Enemy carrier, launching hundreds of waves of Wasps.

Gameplay

This game is divided into 2 phases. The first phase is Carrier Defense phase. After that, the game moves to the Fighter Attack phase. This completes one level. There are multiple levels, each of increasing difficulty.

Carrier Defense

The screen displays the WSS White Giant in the center of the screen, floating somewhere in space. This carrier launches C-24 fighters to protect itself against waves of enemy Wasp fighters. The fighters automatically engage each other, but the Wasps will take pot shots at the White Giant if they get close enough. C-24s and Wasps can be spawned at any time, enhancing the user's feeling of partaking in an epic space battle.

In addition to these fighter dogfights, the OoO sends waves of Destroyer Strike Wings (one destroyer escorted by many fighters) to attack the carrier. The arrival of a destroyer strike wing signals the start of a trial. At the beginning of a trial, an arrow may or may not appear over the carrier, pointing either up, down, left, or right. This arrow is sometimes accompanied by a klaxon. Shortly after that, an enemy strike wing appears from one of the four directions and heads towards the White Giant. The arrow correctly identifies the direction of the attack most of the time, but is wrong approximately 25%.

At any time, the player may press the up, down, left, or right arrow keys to shoot an EMP blast in that direction. This blast stuns enemy Wasps and devastates Destroyer shields, helping the C-24s destroy enemy ships. This blast has a cooldown and gradual recharge (similar to a capacitor), so spamming it is not a good tactic.

The White Giant is also equipped with a Close-in Anti-ship Turret (CAT) that automatically shoots at enemy ships that are extremely close to the carrier. Although this weapon is powerful, it can be overwhelmed if enough enemy ships are present.

Possible Added Mechanic (I cannot add any simultaneous tasks to this game as attention must not be diverted from the approach of a ship for experimental reasons, but I am worried that just watching ships dogfight and occasionally shooting an EMP blast is not engaging enough)

Fighter Attack

Five C-24 ships appear on the bottom of the screen, arranged in a vanguard that spans almost the entire length of the playing field. One of these fighters is yellow, indicating that it is the player's ship. Above the player's ship is a targeting reticle.

Enemy ships appear from the top of the screen, scrolling down and shooting at the WSI fighters on the bottom. If an enemy moves close enough to the reticle and it changes from blue to red, this indicates that the player's ship has a lock and pressing spacebar will fire a missile. The player only has a small number of missiles, so firing them without a lock is wasteful.

The other C-24 ships fire at the incoming Wasps, but without the player's help will likely be destroyed by the many waves of attacks.

Scoring

Cash is awarded for each Wasp or Mantis destroyed in either phase. A special cash bonus is awarded for destroying the Mothership at the end of the last level.