Gunbird uses anime-styled character as the player's chosen craft. A story plays out in between levels and before boss fights, telling a tale of how the protagonists are trying to collect pieces of a magic mirror to make a wish.
When player collides with the body of an enemy unit, player loses a shot power level, and the P item flies around the screen and disappears as soon as it reaches the edge. If player's fighter is at the lowest level of shot, player loses a bomb instead.
Each character in Gunbird has three attacks:
- Normal shot: Tap A button.
- Special shot: Hold A button until pose is changed, then release.
- Bomb: Press B button. It uses 1 bomb stock. When bomb blast occurs, all enemy enemies are destroyed, and player's fighter is invulnerable.
- P: Increase shot power. If fighter is already at maximum, player gets 2000 points.
- B: Increase bomb stock by 1. If fighter already has 6 bombs, player gets 10000 points.
- Bonus: Obtain this Coin-shaped item increases score by 200 points.
- Ash (アッシュ): A 28-year old German man with a jet pack on his back, who in some of the scenes between battles is discovered to be a pedophile, and when 2 players choose Marion and Ash as cooperative partners, he takes an unhealthy interest in her.
- Marion (マリオン): A cute 13-year old witch from England who flies on a broomstick. She is accompanied by her talking pet rabbit, Pom-Pom. She frequently abuses the poor creature verbally and physically. She's fun-loving and thrill-seeking but also selfish, and has a mean streak (which Pom-Pom is often witness to).
- Valnus (バルナス): A big, fat robot created in Russia 6 months ago. Has some of the best firepower in the game. Secretly wishes to be human.
- Yuan Nang (ヤンニャン): A strong-willed and courageous woman whose character design is highly influenced by that of Sun Wukong from the Chinese classical novel Journey to the West, including a cloud-somersault parody, Ruyi Jingu Bang, and the size-changing headband that was used by the monk Xuánzàng.
- Tetsu (鉄): A strong, white-haired old man of 60 years. He is homosexual in a rather uncloseted manner and even calls himself a "faggot".
Marion and Valnus also appear as selectable characters in Gunbird 2 (though Valnus is renamed Valpiro).
There are 7 stages in each game loop (2 loops total). The first 4 stages are randomly chosen from possible 5.
At 2nd loop, enemies fire denser bullet patterns moving at faster speeds. Stage 2-1 takes place at the only stage not available in 1st loop, instead of the 1-1 counterpart. The remaining 3 stages are chosen in random, but does not include the replaced stage.
After completing 1st loop with only 1 player, player can choose 1 of 2 choices for a wish with magic potion, with unique ending for each choice. If 1st loop is completed with 2 player, a combination-specific ending is played.
The cutscenes between the battles with 2 players fighting cooperatively are frequently packed with hilarious dialogue and situations. This is often a recurring theme with Psikyo games, the Gunbird games being no exception. There are no cutscenes when playing 2nd loop stages.
Korean arcade version
It contains English dialog, but some sound samples are missing during play. That was fixed in World version.
Differences in Mobile Light Force
- A Charlie's Angels-style cover picture, completely unrelated to the original characters or the game's theme.
- Character names were changed to those of XS' employees.
- Removal of the fan art gallery from the game (although the directories are still intact on the disc if inserted into a PC).
- Removal of all in-game plot, including the game's ending.
Playstation 2 version
PlayStation 2 version of the game was based on arcade version.