The G-3 served as a test platform for the magnet coating technology later used in Amuro Ray’s RX-78-2 Gundam and other RX-78 series units. It featured the NICN system, an advanced version of the learning computer also implemented in the RX-78NT-1 Gundam NT-1. Additionally, the G-3’s thermonuclear reactor received a new laser accelerator, doubling its maneuverability compared to the RX-78-2.

The G-3 closely resembles the RX-78-2, but features a gray and light purple color scheme designed for reduced detection.