|Number of players||Two alternating turns|
|Input methods||3 Buttons|
Eagle was a bit of a different game upon release, as it was still new to have a game where enemies and their attack patterns would change with every screen or two, as games with enemies and attack patterns that remained the same (such as with Space Invaders and Galaxian) were still popular. The game was also unique by not having three lives per game (as most did back then), but three different ships ("rockets") that varied in size and firepower, plus players could also dock their ships (if they made it far enough in the game) for extra firepower, predating this well-known feature later found on Galaga.
Enemies start off at the top of the screen and fly around in various attack patterns, making their way towards players’ rockets located at the bottom of the screen. An enemy will re-materialize at the top of the screen if they get past a player’s rocket without being destroyed (except for Comets). After several screens, players will get a chance to dock their rockets for bonus points and additional firepower. The current stage rocket that is in use will be raised up to about the middle of the screen while the next stage rocket appears at the bottom. Pressing the fire/retro button will cause the current stage rocket to thrust away from the next stage rocket. If the player is successful with a docking, upon entering the next stage, the two rockets will be joined together, adding to the player’s firing capability.
Colliding with any enemy or not docking correctly will cost the player a rocket and the game will end when there are no more remaining rockets.
- The first stage rocket is small and only shoots one missile from its center. If the player gets rammed by an enemy after docking with the stage 2 or even stage 3 rocket, the stage 2 or 3 rocket can be destroyed, leaving the player with having to start over with the stage 1 rocket again.
- Although made famous by Galaga, Eagle predated the increased firepower function via docking sequence by a year. However, with Galaga, ships were side by side after docking, but with Eagle, the ships were stacked on top of each other vertically.
- Eagle is a copy of Moon Cresta.