ĭevelopment of Gradius IV lasted for roughly ten months - midway through development it was put on hold while staff was shuffled. Several stage ideas were cut from the final game as the team had disagreements over how they would function, most notably a puzzle-like stage where the player shot reflective spheres to open up passageways. A 'boss rush' segment was added as the idea was popular among other Konami staff. Some stage ideas, like the 'volcano' theme in the fourth level, were incorporated from other Gradius games, with the majority being original ideas.

The first stage, featuring large, reflective metal planetoids, was a sort-of homage to Gradius II and its first level, which had fire-coated planets with large dragon-like enemies bursting out of them.

As the first game in the series to use 3D graphics, the team focused to make stages take advantage of this. The project's theme was 'interactive', signaling that levels should be engaging and react based on the player's movement and actions. One of the team's biggest ideas was the stage designs, as they wanted them to feel fresh and new, as well as being distinct from previous Gradius titles. Several stage ideas in Gradius IV were scrapped as the team couldn't decide on how they would work, such as this 'puzzle stage' concept where the player shot reflective spheres to open up passageways. The laser is the twin laser seen in Gradius III. The double mode is the tailgun, seen in other configurations.

Configuration 6: The missile mode is the flying torpedo, which produces two missiles that fly forward in front of the ship.

The laser mode is a thin armor-piercing round that can penetrate multiple enemies. The double mode is the standard 45-degree angle split. After a short delay, the mines explode, yielding a large explosion.

Configuration 5: The missile mode is a vertical mine that is released above and below the ship.

The two new configurations are as follows: In this game there are a total of six configurations, the first four of which are migrated from Gradius II. The seventh powerup category was the one that was labeled '!' and would produce detrimental results, such as reducing the speed or eliminating the weapons of the ship. First of all, the edit mode has been completely eliminated, as are the 'Snake Option' (s.option), the 'Reduce' shield type, and the seventh powerup category. However, several changes were made on the weapons system in the transition from Gradius III.

The core gameplay of Gradius IV remains relatively unchanged. The player's ship, the Vic Viper, exchanging shots with golden dragon enemies in the first stage.

Gradius Gaiden