Eclipse is a 4X strategy game where you must lead your civilization to prevail over the others. Players can choose to play as either a human or alien civilization. On each move, a player takes one of six actions: building, exploring, influencing, moving, researching or upgrading. For example, exploring opens up a new tile in a direction chosen by the exploring player. Each action uses resources (money, materials or science), and resource management is a key part of gameplay.

The galaxy is laid out in three rings of hex tiles, most of which get laid during exploration. At the start of play, only the galaxy center tile and tiles for the players’ respective home stars are laid. When exploring, a player chooses a tileless space which is accessible from a star the player occupies. The player then draws a new hex tile from a stack of face-down tiles and lays it in the chosen direction. The player may strategically choose which orientation the tile takes, to create links to existing tiles or to block access by other players.