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 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.
There are three ship types to select from, with alternate characters for player 2, giving 6 characters in total.
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.