The 1999 edition of Space Invaders rebuilt the game from the ground up. It was fully colored and modeled in 3D with a new feature involving special attacks, based on a variety of aliens with different abilities. Hitting four of the same type of alien would grant one special missile to the player, fired with an alternative fire button which can be changed in the game's settings.
The game boasts an original soundtrack (Never officially released) and bank of sound effects, unlockable game modes and Easter eggs, as well as several references to the original Space Invaders. There is also a 2-player mode, which adds a second, yellow tank (Player 1's being blue) to the action.
Players can save their progress at any point.
The game also had something of a storyline. An opening cinematic shows a pilot of a new style of tank, driving it around a desert base, presumably on Earth. The pilot drives to the fence around a 'Tank Graveyard', containing 3D versions of the original Space Invaders tank, dilapidated and falling apart. A sign notes that the graveyard honors "Those who fell in 1978". As the pilot nods approvingly, a siren begins blaring in his cockpit.
The monitor inside the tank informs the startled pilot that aliens are attacking. The pilot spots them in the sky with his highly technical helmet, and identifies four aliens; one each red, blue, yellow and green. These four aliens are quickly joined by a large force of the same types.
The pilot wastes no time opening fire on the aliens. He destroys them all by striking one and causing a chain reaction explosion, at which point the cinematic ends.
After completing the game, another cinematic is shown. The pilot faces one quick-moving yellow alien, which he eventually manages to shoot down. The pilot is then shown being awarded a medal outside The White House, and salutes the camera.
Meanwhile in space, a disgruntled alien inside a large mothership strikes his monitor when it reveals that all his alien fighters have been destroyed. He warps his ship to a huge grey spacecraft, lands it in the hangar and projects the Earth into the centre of the room. The large craft then warps back to Earth and unleashes a great number of the large motherships onto the planet.
The gameplay of the 1999 edition is very similar to most versions of Space Invaders. The player controls a tank which can move left and right, and fires a single missile when the fire button is pressed. The alt-fire button will fire a special missile if the player has hit four alike aliens in a row. Each level presents an arrangement of aliens which start moving slowly from one side of the screen to the other, moving down slightly whenever they reach the right or left. The player must destroy all the aliens before they reach the bottom, while avoiding their bombs. If the aliens do reach the bottom, they will swoop onto the player's tank, destroying it. If the player has any lives left the aliens will move halfway up the screen and the player can continue to try and destroy them. Throughout each level, a number of mother ships may fly across the top of the screen. These mother ships pose no danger to the player, but drop numerous power-ups when hit;
- Shield, which covers the player's tank in a shield, saving them from most attacks - but only once.
- Double Shot, which allows the player to fire one extra missile quickly after their first, so that two may be on screen at a time instead of one. It is very useful for bosses.
- Time Stop, which freezes all aliens and bombs for a few seconds, making them easy targets for the player.
- Max Energy, which grants the player the special missile associated with the last type of alien they hit. If the player has an empty energy bar, the power-up grants the player that level's special alien's missile.
If a player loses a life, their double shot power-up will become inactive and their energy bar will be emptied.
The game has a number of stages which change depending on the difficulty selected by the player. Each stage takes place on a different planet, and displays an information screen at the beginning, telling the player a little bit about that planet's special alien. After each planet's fifth level, the player is warned of "Incoming mother ships!" These levels give the player a chance to earn some extra points, as well as an extra life if they can hit five mother ships. After the planet's tenth level, the player faces a boss alien, unique to each planet. Defeating a boss also grants an extra life.
Some levels have a number of bunkers above the tank. These are resistant against alien projectiles, but will turn slightly more red each time they are hit. Eventually, they will be destroyed if hit too many times. The player can use these to a particular advantage by firing at them from beneath, which damages the bunker but also moves it upwards. Any alien that crashes into a bunker is immediately destroyed.
Stage 1 - Pluto
The only planet without a special alien, Pluto provides simple configurations of a few of the basic four aliens (Red, Yellow, Green and Blue) and lets the player get used to using their special abilities. The first four levels are made up exclusively of one type of alien and are set up to make the aliens especially vulnerable to the special attacks hitting four in a row will provide.
Red - These aliens give the player a 'Vertical Burst' missile, which continues to fly upwards even if it hits an alien, allowing the player to destroy an entire column of aliens if they are moving slowly enough. The bombs dropped by these aliens, gas-blue tear shapes, can be destroyed.
Blue - These aliens give a leftwards burst missile. This missile flies up until it hits an alien, at which point it flies leftwards, destroying anything in its way. The only time this does not take place is when it hits a mother ship. These aliens' bombs, rainbow-coloured lines, cannot be destroyed.
Green - Identical to the blue aliens' missile in all respects, but flies rightwards. Green alien bombs, which are short green arrows, cannot be destroyed.
Yellow - Provides a 'Diagonal Burst', which flies straight upwards, but upon impact with an alien splits into two arcs which fly in opposite diagonally upwards directions. Very useful against large numbers of aliens in lots of rows. Its small, ovular, yellow bombs can be destroyed.
Boss - 'Squashie' or 'Crusher'
Pluto's boss is the only alien in the game which does not fire anything at the player. Instead, it roars and then swings down to the ground, attempting to crush the player. Its attacks are modified depending on how much health it has:
- At 100% - 66% health, the boss simply flies down and flies back up again after hitting the ground.
- At 66% - 33%, it will 'swim' to whichever side of the screen the player is on after hitting the ground. If the boss 'swims' over the tank, it will be destroyed. The only way to avoid this is to move to the extreme side of the screen after the boss hits the ground, and move back out of the way after it is done 'swimming'.
- At 33% - 0% health, the boss will rapidly move up and down towards the player after hitting the ground, striking it multiple times.
Stage 2 - Neptune
Special - 'Switcher'
The cyan switcher alien takes two shots to destroy, as do its projectiles. It only awards energy on the first hit. It awards the player 'Swarm Missiles' after four have been hit. This useful power identifies the most numerous alien on screen and unleashes missiles at approximately 8 of them, which do not require aiming and will seek out the aliens themselves.
Boss - 'Ladybird' or 'Shell'
Neptune's boss originally flies onto the screen boasting two large, red wings and a powerful cannon shielded by a forcefield. Every few seconds it will fire a number of green, spiral-shaped bombs in random directions, creating small moments of bullet hell for the player. These bombs cannot be destroyed. To defeat this boss the player must first destroy both of its wings. When this is done the forcefield around its cannon is deactivated, and the cannon is then vulnerable. The boss will roar at the player, then take center screen and unleash a huge tide of bombs. Once it has done this the boss will continue as it did previously, moving faster. When the cannon is destroyed, the boss is left as a fraction of its former self, and starts flying down to try and crush the player, a la Pluto's boss. It is very easy to destroy at this point, but caution should be observed as it flies down very quickly.
Stage 3 - Uranus
Special - 'Blocker'
Blockers are crimson and grey aliens which drop flame-shaped projectiles. These can be destroyed by the player. When the blocker is destroyed it will usually deploy one or two flaming wings to each side of it (unless there is another alien in the way). These wings cannot be destroyed but disappear after a few seconds. Players should be careful and try to avoid the blocker being the last alien on screen as these wings can still destroy the tank if they get low enough. Destroying four blockers in a row grants the player a 'laser blaster', which shoots a huge beam into the space above the tank for a few seconds, destroying the majority of aliens it touches - including mother ships. Unfortunately, in PSX emulators, the laser is invisible.
Boss - 'George Harrison' or 'Rotator'
Nicknamed for its beetle-like appearance, this boss presents an interesting battle. It flies onto screen, then inverts itself. Two small cannons on its back fire synchronised spinning bombs at the player, and must be individually destroyed. When they are, the boss turns the right way up and starts unleashing arcs of larger projectiles all over the screen. These can be dodged with relative ease, but the boss may also fire large spheres at the player which must be dodged more carefully.
Stage 4 - Saturn
Special - 'Angler'
An irritating and challenging alien, particularly on the harder difficulties, Anglers are named as such because they tilt to one side and fire projectiles at angles. These projectiles are especially frustrating as they can bounce off the left or right edge of the screen before hitting the ground, making bunkers less safe, AND they cannot be destroyed. Hitting four Anglers awards a 'boomerang' shot, which does not fire a missile, but rather a large green arc which spins around the screen in a large circle, returning to where it was fired from. This weapon is hard to use effectively but can be very helpful for destroying hard-to-reach aliens.
Boss - 'Doughnut' or 'Circle'
This large, circular boss is quite unique. It descends as a large ring around the tank with three modules attached to it. The leftmost module is perhaps the most dangerous. It fires a number of large bombs in quick succession if not destroyed rapidly. Rightmost is a large laser beam generator, which fires a thick beam down the middle of the screen when it is positioned correctly. The largest module, the central one, is armed with an array of cannons, but also occasionally sucks in the space around it to heal itself. Doughnut's modules alternate positions, but only one can attack at a time. The easiest way to defeat it is to start on the left and fire as much as possible into the bomb module, destroying it, then when it is safe to do so, move to the right and do the same to the beam. Doughnut will then move his head module to the right, where the player cannot be hit by his cannons, and it is a simple matter of firing as fast as possible into it to destroy him.
Stage 5 - Jupiter
Special - 'Freezer'
Freezers are distinctive, pterodactyl-shaped aliens, bright turquoise in colour. They drop a projectile identical to that of the red alien (and like theirs, it can be destroyed), but they also have a unique attack. If there is no other alien in front of a freezer it may at any time fly down to the ground, where it will hover above the level of the tank, moving slowly. Every two seconds, it will fire a laser beam, lasting two seconds. This laser beam will cut through a shield and destroy the tank immediately and should be avoided. Multiple freezers may fly down at once, though if one lands on another it will usually remain there until the one below has been destroyed. Destroying four freezers will grant the player an 'Acidic Cloud' missile, which flies up as a normal missile but upon impact will turn into a slow moving yellow orb, destroying everything it touches (including mother ships). Acid clouds move gradually to the top of the screen, where they vanish, usually slightly to the left or right.
Boss - 'Sticky' or 'Bunker'
Named for his slender limbs, Sticky flies onto the screen and then four T-shaped shields appear beneath him. Sticky flies to the space above these shields and bombards you with fast-moving bombs. Mercifully, these bombs can be destroyed, if you are quick enough. To defeat sticky, fire at his shields until they disappear. He is extremely vulnerable and easy to destroy once this is done.
Stage 6 - Mars
Special - 'Burster'
Bursters have a tendency to rain projectiles down like there is no tomorrow. Thankfully, these can be destroyed. This bad habit unfortunately continues after they are destroyed, as they live up to their name by bursting into eight slowly descending projectiles. These can also be destroyed but are a hazard as well as an obstruction, and the time spent dealing with them can lead to aliens getting uncomfortably close. Destroying four Bursters grants a 'Sine-Wave Missile', which fires upwards in a zig-zag pattern.
Boss - 'Pulse'
Named for its deadly laser, this boss is actually three units attacking at once. They move up and down, shooting multiple lasers after each move. When one is destroyed, the other two begin to move in multiple directions and tilt. When one remains, it moves, tilts and fires lasers constantly until destroyed.