Originally developed for the arcade, Batsugun saw two revisions—the first being released in 1993. The latter named Batsugun Special Version was shown at the AOU (Arcade Operators Union) show in Japan but was never released as Toaplan slid into bankruptcy. After Toaplan's bankruptcy the Special Version appeared on the secondhand market. The two revisions were released on the Sega Saturn in 1996 as a single package coded by Toaplan offshoot Gazelle.
Heralded by some as the first "manic shooter", Batsugun involved employees who would go on to form and work at Cave and continue to work in this subgenre. Batsugun saw an evolution in the use of complex enemy wave and bullet patterns, and player firepower and hit-box.
As is the standard with most arcade shooters, the player controls their ship with a joystick and two buttons. One button (Fire) shoots the main guns, and the other button (Bomb) releases a smart bomb that spreads huge energy balls all around the player's ship.
As enemies are destroyed, the player gains experience points that are separate from the score. For every 288 experience points gained, the main gun will 'level up', becoming much stronger. This is analogous to experience points and levelling up in role playing games. The weapon can only level up twice, so after it has achieved its maximum level, 288 experience points will grant the player an extra bomb.
The player can also grab "P" icons to increase the power of the current level gun. A maximum of five "P"s can be collected per experience level; getting more after this gives extra points instead.
Collecting "B" icons increases the number of bombs, to a maximum of 7.
Skull Hornet Pilots & Ships
There are three ship-types and six player-characters to select from.
- Ship Type A: has a simple array of rapid-fire energy-beams that spread evenly. As it levels up, the beams become wider and more powerful; the ship fires missiles as well.
- Pilots: Jenno & Schneider
Jenno is an attractive teenage boy with cybernetic enhancements and a tragic past. Schneider is an old man who was once awoken from cryogenic sleep.
- Jenno's quotations:
"Here I come, come, coooooooooooooooooome!"
"You would never be ready to challenge me!"
- Schneider's quotations:
"The number of mysterious enemies is just the number of adventures I'll enjoy. Yes!!"
"The number of invaluable enemies is the number of dreams I'll enjoy. Yes!"
- Ship Type B: shoots a straight beam of lightning for as long as the Fire button is held. Tapping the Fire button causes sparks to appear and travel along the beam; this may or may not do more damage. As it levels up, the lightning becomes wider and multi-colored; and secondary projectiles are launched as Fire is tapped.
- Pilots: Beltiana & Alteeno
Alteeno and Beltiana are both attractive teenage girls. Beltiana is a long haired young lady looking to avenge the deaths of her family. Alteeno, a tomboyish pilot prodigy, doubles as the Skull Hornets' mechanic.
- Beltiana's quotations:
"You'll never get anywhere with me at this level!"
"You're not going to fly in front of me that easy."
- Alteeno's quotations:
"I'll scrap you if you try to challenge me!"
"What a junky ship! Let me maintenance it!"
"Ha, ha, ha."
- Ship Type C: this ship is fairly adaptable; holding Fire will shoot energy waves straight forward, whilst tapping Fire will fire a spread of projectiles. As it levels up, it will fire homing missiles, and acquire small "drone" ships with their own firepower.
- Pilots: Iceman & Olisis
Olisis and Iceman are both attractive young men: Iceman is a 'cool' long haired fellow of unknown origins. Olisis is also the Skull Hornets' founder and director as well as the prince of his planet who hopes to stop his father's cruel ambitions.
- Iceman's quotations:
"I'm as cool as ice."
- Olisis's quotations:
"Father is wrong. I must stop his evil deeds."
"You're saying you are challenging me!?"
The enemy "bosses," in order of appearance, are:
- Code Name: Deep Purple
- Code Name: Madzella
- Code Name: Mad Steel Darkness
- Code Name: Jupiter
- Code Name: Ground of the Galaxy (Garaxy?)
Apart from destroying enemies, points can be gained from collecting golden V-shaped medals. After the level is finished, 3000 points are awarded for every small one, and 5000 points for every large one.
If the player's ship is destroyed during a level, all medals collected are lost.
An extra life is awarded at 1,000,000 points.