Geometry Wars: Galaxies is different from previous Geometry Wars games in a few key ways that will be addressed here.
For the first time, you now have a drone that follows you around. There are several ways your drone can behave, all listed on the drones page. It is important to know and understand the value of each different behavior when playing the game. Drone behaviors are unlocked using geoms, the currency within the game.
Geoms are gained simply by defeating enemies. Besides purchasing drone behaviors, they are also used to unlock planets and systems. But they have another, very important use as well. In previous Geometry Wars games, you earned extra lives or bombs or changed your weapon by gaining points—all of that is now controlled by geoms.
Lastly, there are many new enemies! Though you won't encounter most of them until after the first system, feel free to get a look at them now.