I have one that I first penned in 2008.

Opening cutscene
A normal convenience store is robbed by several men. Only moments after the initial stick-up, more men burst in, guns high in the air. At this moment the clerk is bemused slightly that dozens of people are holding him up, and even more robbers shove themselves into the store. 100 men in total arrive, pushing and shoving, all trying to rob the store and shoving what they can get their hands on in their pockets. No sooner does the last robber enter when police begin to surround the perimeter, shouting for them to come out and give up peacefully. One person runs out, gun in hand, and refuses to go down without a fight.

Gameplay
The player is given 100 lives at the start, with no opportunity to earn more during play. No option to continue the game after all lives are lost is available. Up to four players can play simultaneously; this will reduce the overall difficulty, however, all players will share the 100 lives between them. If a player dies with 0 lives total remaining among the group, that player is eliminated from the game. The game ends and scores are tabulated after the last player’s game ends.

The convenience store is shown at the bottom of the screen, with its door at the bottom center, and the playfield is a large rectangular arena sealed off with stationary police vehicles and other obstacles. The game starts with one robber, controlled by the player, exiting the store. The player is capable of moving anywhere around the field in two dimensions and is armed with a basic gun that fires one round when the fire button is pressed. More powerful weapons, including rifles, machine guns and even rocket launchers, can be obtained with prolonged play. There are two fire buttons. One will always shoot a round from the default gun, while the other will fire a round from the secondary weapon if the player has one in his possession; else, it will fire the default weapon.

The player loses lives in one of three ways:

1. The player character takes a hit from an enemy’s weapon.
   
2. The player character makes direct contact with a police officer (player is handcuffed and apprehended).
   
3. The player character touches an environmental hazard.

All of the above scenarios will cause the player to lose one life. If the player is killed or arrested, a new robber will exit the store immediately after the previous robber is apprehended, until all of them are incapacitated. The pacing and difficulty curve is designed to drain the player’s lives quickly. Scoring is determined primarily by the length of time the player endures the police attack and secondarily by the number of kills the player scores. One point will be awarded per officer wounded, with more points awarded for more powerful enemies and machines destroyed. This number is multiplied by a factor, a number greater than or equal to 1, determined by the duration of the player’s game to determine the player’s final score, with longer times awarding exponentially higher scores. The number of deaths is tabulated at the results screen, breaking down causes of death (arrest, gunshot, explosion, etc.)

The setting can be changed to similarly high-risk areas, such as banks or jewelry stores, with only minor adjustments to the terrain and police response needed for increased variety.

Weapons
The player has access to a large cache of weapons throughout the game, and all of them come from fallen enemies.

• Default weapon. A basic semi-automatic handgun with infinite rounds and no firing delay.

Automatic weapons:

• Machine gun. A generic submachine gun with 200 rounds. The bullets disperse slightly after one-half screen’s length, but this is a minor deterrent to accuracy. Machine gun rounds are weaker than that of the pistol.
  
• Heavy machine gun. A much larger weapon with a bigger caliber, 150 rounds and less accuracy than the Machine gun. While the player is firing this weapon, his movement speed is reduced by 20%.
  
• Assault rifle. 120 rounds fire straight and fast. Bullets fire in full auto when the fire button is held down but will fire in three-round bursts with a single press.

Rifles:

• Semi-automatic rifle. The player is advised to spend its 99 bullets wisely, as this weapon boasts the highest speed and accuracy of all of the firearms, next to the Sniper rifle. One shot is fired with each button press. It is the most common subweapon available.
  
• Assault shotgun. The wide dispersal pattern of the shotgun makes it the ideal crowd stopper at medium distance. At point blank, it can prove devastating to any large enemy. A 1.6 second delay between shots precludes rapid destruction. The 30 shells must be spent carefully for maximum effect.
  
• Sniper rifle. The sniper rifle will automatically target the nearest enemy in the player’s general direction and cause massive damage immediately after the trigger is pulled. As long as a target is in range, it will not miss. It holds 8 rounds, with a 3-second delay after each shot.

Explosives and incendiary devices:

• Grenade launcher. Grenades have moderate blast radius and spray shrapnel in all directions to cause damage. If a single enemy stands over the grenade when it detonates, it will be the first to absorb much of the shrapnel, thus taking maximum damage. Tight groups will face similar devastation if a grenade is at their feet. Grenades come in packs of six and can only be thrown once every five seconds. After three seconds, a grenade will detonate, at which moment the player must take care to be clear of its explosion.
  
• RPG. The rocket-propelled grenade has identical power to its timed counterpart, with the added strength of a high-impact explosion in addition to the shrapnel of an ordinary grenade. Six rounds can be fired, with a two-second delay.
  
• Molotov cocktail. One crude firebomb can set an area ablaze for 10 seconds, causing constant damage to anything in its range for as long as it burns. The player must decide where to throw it carefully as he gets only one chance to make it count.
  
• Flamethrower. In terms of dispersion, the flamethrower is unmatched. Its only drawbacks are its lack of range and speed. The flamethrower is equipped with enough fuel for 15 seconds of continuous incineration.

Others:

• Sword. The sword can be swung an infinite number of times and damages the enemy for every frame it makes contact. The sword has no equal in terms of destructive power and is the ultimate close-range weapon, especially when cornered. For this reason, it is exceedingly rare and is only carried by super enemies.

Adversaries
When the action starts, police begin entering the arena, at first approaching the robber with caution. Initial forces are limited to single officers, but soon escalate into large swarming groups, strike officers with riot shields and other protective gear, robots with small arms fire, autonomous turrets and “supercops”, capable of taking many hits from even the most powerful explosives. Enemy firing patterns also become very dense and danmaku-like, and later enemies will come armed with their own high explosives. Bombs will enter the field and the player will have to disarm them without firing any weapons at them. It will become very evident after only a few minutes that this is no ordinary police force, as they will employ many means of counter-action against the petty criminals controlled by the player well in excess of what is considered “excessive force”. After a long period, the enemy forces become more surreal, with androids and even tanks joining their ranks.

Enemies include:
Personnel:

• Single police officers. These are the most common threat and can fire bullets in any direction, although their firing rate is very low. One clean shot can take most of them down.
  
• Veteran officers. With higher speed and a faster firing rate, this enemy is otherwise similar to the normal cop. Some of them may have bulletproof armor, but enough shots will still destroy them.
  
• Detectives. Although they do not carry firearms, they do wield an equally threatening weapon: handcuffs on chains. They can sling the cuffs in eight directions very quickly, and remain a threat until they return to the Detective’s hands. Touching the cuffs at any time will result in instant arrest. Their faster speed is a result of their lack of armor, making them very vulnerable to any weapon.
  
• Sergeants. Their shotguns and heavy armor should make them a priority in engaging multiple targets, especially since they tend to arrive with other officers.
  
• Supercops. A true menace, especially in groups, these large cops are very tough to take down, requiring many shots with the default weapon to fell. They normally come equipped with a riot shield and can wield any weapon, from shotguns to chain-cuffs to small explosives.
  
• Soldiers. The first will appear after 10 minutes of play. Armed with rifles and machine guns, the high firing rate and bullet speed of these Army and National Guard soldiers make them a very potent threat. After 20 minutes, they will replace the police force entirely.
  
• Supersoldiers. Even more powerful than their police counterparts, they are equipped with even tougher armor and can wield any weapons in any combination.

Robots:

• Patrol robot. A small robot on tank treads with a camera, antennae and possibly a small remote-controlled firearm. They can move in only four directions, although their weapons can aim anywhere. Their firing rate is low. Ideally, the robot can be disabled if shot several times from the front, although they can be impaired in several ways if they are hit anywhere else:
  
  1. A hit on the side will take out one of the treads and cause hampered movement. Note that this may cause the robot to fire wildly. Attacking from the side should be avoided if possible.
     
  2. Complete loss of sight will result from a hit to the back. The robot will cease fire and continue moving in the direction it was last moving until it hits an obstacle; this allows the player to take the robot out at his leisure. Because the robot is always fixed on the player’s position, this can prove difficult.

Androids. Humanoid robots have no better place than in a game such as this. They can emulate any of the above human enemy types, although which type they are designed to clone will not become evident until they attack.

Swarms. There are two types of swarms: one will appear to be a tightly-knit swarm of locusts; the other is a mass of beetles. It will either crawl or fly low, depending on the type, and try to overwhelm the player with sheer numbers. If the player is unable to escape them for three consecutive seconds, this is exactly what it will do. It will take longer for a smaller swarm to destroy the player. While a reasonable number of shots with the default weapon will destroy the entire swarm, much fewer shots are needed with a spread-shot or automatic weapon, respectively. With the flying swarm, each shot will cause the swarm to disperse and regroup to a smaller mass. Because of this, it is recommended that the player time his shots well and not fire wildly into the swarm.

Vehicles:

• Patrol cars. Occasionally a police car will enter the arena carrying two to five officers. The player must take care not to get run over. They can stop anywhere in the arena, and when they do, all of the officers will exit and attack immediately. The car itself can be used as a shield when all of the officers who occupied it are downed, and should be used as such against larger enemies and weapons. However, any round, enemy or player, will damage the car. The car will explode when it sustains too much damage. The explosion will not cause damage to the player or enemy.
  
• Tanks. Overkill if I ever saw it. Tanks cover approximately one-fifth of the screen and will only appear every 30 minutes. They are extremely difficult to destroy and are occupied by an indefinite number of officers and military personnel. One will exit the tank and engage the player directly after a regular period. While it is easy to take the tank out from behind its cannon, caution should be taken while moving around the tank as it can crush the player instantly with the slightest contact. The main cannon’s shell is highly explosive and can catch the player in the blast if he gets careless.
  
• Helicopters. After 10 minutes, helicopters will arrive on the scene to transport human adversaries into the fray. They are infrequent (appearing one at a time after a random period of time larger than 5 minutes) and can carry up to eight enemies. The helicopter cannot be attacked and will leave after all of its passengers land, but until then, it will obscure approximately 1/7 of the screen.

If I do, it's going on WiiWare.