Galaga arrangement

In 1995, Namco rereleased this game and a game titled Galaga Arrangement, a remake of sorts. The game featured a number of changes from the original:

Music and sound effects have been altered.
Rounds have been named; one is called the Asteroid Field, and the background varies (such as asteroid belt, nebulas, etc.).
When a boss Galaga captures a fighter, a player can shoot and retrieve the fighter while the boss Galaga is still in formation. Also, the game does not stop while the fighter comes back; game play still goes on.
Boss Galagas have been split into three different types: yellow, green, and red. Green has a stronger, bigger shot; yellow gives rapid-fire; and red gives reflecting shots.
Boss Galagas still use tractor beams even if the player has a double-ship; the boss Galaga simply steals the ship.
In Challenging Stage, there are more varied formations, and the screen tilts around, making it tougher to secure a lock on the Galagas.
There are more varied formations; Galagas come in different ways now, and there may be 2-3 formations before completing a stage.
A screen (intermission) after beating a stage will pop up, stating destroyed-to-miss ratio and percent of defeated Galagas.
Shooting rules have been considerably relaxed, with the player able to shoot more rounds faster than in Galaga
It appears that simultaneous two-player action may be available.
By inputting Left-Right-Left-Right-Up-Down-Up-Down, the game displays a clock at the bottom of the screen, showing total time played in the game. The clock does not run in the Challenging Stage nor between the intermissions.
30 stages of gameplay, with a final boss at the end of stage 30 named "King Galaspark" (a huge purple and red bug in the "Enemy-Comb Zone").
The game has seen arcade and home console releases. The home version has been released on the PlayStation 2, Xbox, and Gamecube releases of Namco Museum.

This game was released alongside Galaga in the 128-bit version of Namco Museum in 2001.

There are at least four well-known bugs in Galaga

One bug causes enemies to cease dropping bombs for the rest of the game. To trigger it, destroy all enemies but the two bees in the bottom two rows of the left-most column, then wait, dodging their shots for fifteen minutes or so until they stop dropping any bombs. From that point onward until the end of the game, all enemies will effectively be disarmed (but can still be dangerous kamikazes). This bug was fixed in a later revision of the game. The bug is not present in Namco Museum 50th Anniversary because the later revision of the game was used.
It is possible to control the game during its attract mode. During the game demonstration, at the moment that a boss Galaga begins emitting its tractor beam, the game for some reason pays attention to the joystick and fire button. A player can shoot the boss and continue to play the game for a short while. Sometimes the player's ship will move oddly or be invulnerable until the game demonstration ends; sometimes the game will crash and reset itself harmlessly; rarely a switch error will freeze the game on the error screen.
Unless the machine is set on the hardest difficulty, the game "wraps around" from Stage 255 to Stage 0, causing the game to effectively lock up (although the starfield continues to scroll). This is because the game did not know how to interpret Stage 0.
Player 1's score wraps around at 999,990 (and never registers internally as greater than this number), but Player 2's score has been known to display entire scores over 10,000,000.

Captured Fighters Galaga

Perhaps the most famous element of Galaga is the ability for the player's ship to be captured by the enemy. Boss Galagas (the green enemies at the top of the formation) will occasionally stop mid-dive and attempt to capture the player's ship with a tractor beam. If the ship is captured, the boss carries it back up into the formation. If the captured ship is the player's last ship, this ends the game.

The captured player ship acts as an escort to the boss Galaga that captured it, and dives down simultaneously with the Galaga. To free the ship, the player must destroy the Galaga in mid-dive — if the Galaga is destroyed in the formation, the player ship will attack on its own and disappear off the bottom of the screen. (It returns as an escort to another boss Galaga in the next round.) The player can also destroy the player ship, which awards 1000 points.

If the player successfully frees the captured ship, the two ships join together side-by-side at the bottom of the playfield, and they move and shoot together (resulting in a double-shot that makes it easier to hit enemies). However, the combined double-ship is also twice as wide as a single ship, and thus harder to defend. If one of the ships is hit, only that ship is destroyed and the player continues with the surviving one. Because of the obvious benefit of double firepower, a common Galaga strategy is to purposely let a boss Galaga capture a player ship early in the game, then immediately free it.

Contrary to rumor, the double ship cannot be recaptured and released to form a "triple ship". Boss Galagas will only attempt to capture when only a single player ship is in play. However, the triple ship is a feature in the sequel game Galaga '88.

The game differs from Galaxian in several ways

The game differs from Galaxian in several ways:

Two player shots can be on the screen simultaneously.
At the beginning of each level, the enemies arrive in five groups of eight enemies each, which fly in from the sides or top of the playfield and enter formation. Later on in the game, they arrive in groups of 10 or 12, with the two or four extras breaking their flight path in mid-flight to ambush the player. The player can shoot these enemies as they arrive, and they shoot back. Enemies only drop bombs while they arrive or while they are in a dive; they do not drop bombs while in formation.
The boss Galaga, the green aliens at the top of the formation, take two hits to destroy (the first hit will turn it blue).
Boss Galagas occasionally stop in mid-dive and attempt to capture the player's ship with a tractor beam. See Captured Fighters below for more information.
Galaga was one of the first games with a bonus round (after Rally-X), here called the "Challenging Stage." In a Challenging Stage, five groups of 8 enemies (including 4 boss Galagas) enter the playfield, fly in predefined patterns, and exit again. They do not fire at the player, and they do not create a formation. The goal of the Challenging Stage is to destroy all of the enemies before they exit the playfield. If the player succeeds in destroying all 40 enemies, he earns a "Special" bonus of 10,000 points — otherwise, the bonus is 100 points per enemy destroyed. Destroying whole groups of enemies scores an additional bonus of between 1,000 and 3,000 points. Challenging Stages are considerably easier to beat with double firepower.
Starting on Stage 4, a single non-boss enemy flashes as it prepares to dive, and then splits into three special enemies. Two of the copies will fly off the bottom of the screen and disappear if not destroyed — the remaining enemy will continue to dive down from the top of the screen. (In some cases, this enemy may rejoin the formation and turn back into a regular enemy.) Destroying all three enemies yields a score bonus of between 1,000 and 3,000 points, depending on which special enemy appeared.
When the player's ship is destroyed, it is accompanied by an explosion sound effect that is considerably more realistic than the one heard in the original Galaxian.
The game keeps track of all of the player's shots and displays the player's "hit-miss ratio" at the end of the game. In some rare instances, it is possible to finish the game with a hit-miss ratio greater than 100%.
Galaga can be played by a single player or by two players alternating turns (Galaxian is one-player only). The starting number of lives is set to three by default, and an extra life is awarded at 20,000 points, 70,000 points, and every 70,000 points thereafter, but these settings can be changed via DIP switches on the game's motherboard. Two-player mode can be unpopular, however, as it is possible for an experienced player to play his entire game before the second player gets his first turn.

Gameplay Galaga

Gameplay
Galaga is a sequel to Galaxian and has similar gameplay. The player controls a spaceship (which can move only right or left) and shoots at swarms of incoming insect-like aliens which fly in formation above him and occasionally swoop down to bomb him in a kamikaze-like dive. The enemies in the top row will sometimes dive with one or two escorts. Enemies which survive a dive will rejoin the formation from the top. When all enemies are destroyed, the player moves on to the next level.

The three types of enemy each have a different score value. A blue enemy is worth 50 points in formation and 100 when attacking. A red enemy is worth 80 in formation, 160 when attacking. A boss is worth 150 in formation, and its attack value depends on whether it is accompanied by red escorts: 400 points if alone, 800 with one escort, and 1600 with two. This point value is determined when the boss's attack is initiated, so shooting escorts before the boss (or missing them entirely) will still earn the higher point values.

A "rapid fire" chip is available, replacing chip 3J on the original Galaga CPU board. It allows for a continuous stream of fire, as opposed to the stuttered firing limitation of the stock 3J chip.

Galaga is an arcade game

Galaga is an arcade game that was released by Namco in 1981 (and also licensed to Midway Games). It was one of the most popular arcade games and is still sought after by collectors.