Gameplay
The player returns as the role of the pilot of the Vic Viper starfighter to battle the onslaughts of the Bacterion Empire. There are a total of ten levels in the game, with stage 4 being something of a bonus level; here, the player controls the Vic Viper in a third-person perspective and must avoid colliding with walls. Though the level is completely devoid of any enemies, free floating power-ups are scattered throughout. There are also two hidden levels that are based on the early sections of Gradius and Salamander. The game contains the familiar weapons, level layouts, and enemies that have become trademarks of the series.
The original arcade version is known by fans as being considerably more difficult than its predecessors. This version did not provide a way to continue the game upon losing all lives, even as an operator-selectable "allow continue" option. The Japanese version of the game contains a 'beginner mode' that allows the player to venture through the first three levels at a much easier difficulty. At the end of the third level, the game ends immediately and bids the player to try the game again at the normal difficulty. The Asian arcade release lacks the beginner mode and retrospective introduction sequence, but reduces the difficulty overall.
In addition to new pre-defined weapon schemes, Gradius III introduces the "Edit Mode"; players can mix and match missile, double, laser, shield and "special" ("!") power-ups into their own custom combination. Some of the weapons available in pre-defined schemes can not be used in custom schemes, and vice versa.
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