The game gem is how the game handles orbital movement in a manner that it both abstractly simple yet retaining the flavor of orbital mechanics.

For combat within a solar system, a Planetary display is used. This is series of 9 concentric rings of hexes, representing the orbits of the planets of the system. Each ring is called an Orbital.

Note that in reality the scale of a hex depends upon which orbital it is in. For instance, in orbital 6 each hex could be 0.87 astronomical units in diameter, while the hexes in orbital 5 might be only 0.3 AUs. This pseudo-logarithmic scale is required in order to squeeze the entire solar system into a reasonably sized map.

Each of the four races in the game have different spaceship propulsion systems for their ships, with different limitations. Each race has one interplanetary propulsion system and one interstellar propulsion system.

There are three different movement types:

1. Up Well: The orbital the craft is in may not decrease at any time in its movement and at the end of the movement must be at least at one orbital higher (that is, away from the center of the display) than at the start.
2. Down Well: The orbital the craft is in may not increase at any time in its movement and at the end of the movement must be at least at one orbital lower than at the start.
3. In Orbit: All movement must be in the same orbital that it started in and all that movement must be in a single direction (either clockwise or counterclockwise). In addition if moving In Orbit for consecutive turns movement must continue in the same direction.

The Gzrel use a solar sail for interplanetary propulsion and a ram scoop for interstellar. The solar sail may only move Orbitally or Up Well, while the ram scoop may use Orbitally or down well. The first turn must be using the ram scoop. Once a "No Change" movement command is plotted, the ship switches to the solar sail, and the ram scoop may not be used again until the ship leaves the solar system.

The Tassar use a fusion pulse for interplanetary propulsion and a ram augmented rocket for interstellar. The fusion pulse may move Up Well, Down Well, or Orbitally, but expends fuel to use it. The ram augmented rocket may move Orbitally or Down Well. The first turn must be using the ram augmented rocket. Once a "No Change" movement command is plotted, the ship switches to the fusion pulse, and the ram augmented rocket may not be used again until the ship leaves the solar system.

The Terrans use an X-Ray refrigerator laser for interplanetary propulsion and a black hole jump for interstellar. The X-Ray laser may move Up Well, Down Well, or Orbitally, but expends fuel to use it. Once it reaches the 9th orbital the ship may utilize a black hole jump to another star, where it unfortunately appears in the core of the target star. Hence the need for the refrigerator laser.