One of the defining aspects of Gunstar Heroes is the ability to combine two of the four starting weapons into better weapons.
| Force | Lightning | Chaser | Fire | |
|---|---|---|---|---|
| Force | Double Fireball | Rapid-fire Lightning | Chaser Force Beam | Exploding Fireball |
| Lightning | Rapid-fire Lightning | Mega-Bolt | Chaser Lightning | Lightning Saber |
| Chaser | Chaser Force Beam | Chaser Lightning | Star Chaser | Chaser Fireball |
| Fire | Exploding Fireball | Lightning Saber | Chaser Fireball | Ultra Flamethrower |