Dark Nebula has 8 Small boards representing sectors of about six or so star systems. The boards are placed randomly at the start of the game by both players one at a time, to their own advantage. The game is played in turns with each player's turn having a number of phases. Get the money you earn from your star systems, move your ships and combat, a reaction from your opponent (which has some restrictions), a final move and combat by you, then it is the other players turn.
The object of the game varies with the board placement, but basically you need to control your opponents home world for a number of turns.