I played Core Worlds again, and I still like it, but I think I might try a variant idea next time.

The theme is engaging and works well with the mechanics, the player interaction is good and the choices are interesting. But, it is a bit long, and feels like it would be more fun if it was shorter. It also feels like the first couple rounds, where players have the almost-same decks, is less interesting. The game has a nice draft variant which mitigates this, but it occurs to me, you could change the game such that the entire first two rounds are doneas a similar style of draft.

Specifically, with N players, lay out 4N+2 cards from the first deck and have each player draft 4 of them (or pass) in an "S" sequence (1-2-3-3-2-1-1-2-3-3-2-1). If you draft any worlds, you can settle those with Grunts or Snubs. After the draft, shuffle those cards and the drafted "0" cards into your starting deck, and start the game in round 3. This seems like it would retain almost all of what I like about the game, and reduce it's length by 20% or more (the last two "Core Worlds" rounds seem to go quicker than the other 8 rounds). Maybe you'd also want to have a "deployment only" version of round 2 where you can deploy up to your energy production worth of units from an initial hand of 6 to further bootstrap it, but I'm not sure that's necessary.
http://boardgamegeek.com/boardgame/98351/core-worlds
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