Gradius III is very similar to Gradius. It features additional weapons, improved graphics, and new challenges.
Like Gradius, there are three parts of a stage:
- Pre-Stage: in a pre-stage, there is no terrain to deal with and you are free to move anywhere. Enemies appear, most of which are likely to give you power-ups.
- Stage: this is the main part of a stage. There are obstacles to deal with and sometimes the enemies' appearances are themed to match the stage. Each stage has a different theme.
- Post-Stage: this is the boss fight. Unlike Gradius, each stage has a different boss. They each have different attacks, and have a weakpoint that must be shot at several times in order to kill the boss.
The power-up strategy is the same as with Gradius, with a power-up bar, this time with seven power-up types, and 28 different weapons.
In the SNES version, players can continue after dying. In the arcade version, there are no continues.