Crew numbers has been the most important balancing act in the whole game. SSO is largely based on base 6, the challenge deck is 24 cards and each crew arrives with enough oxygen to last 12 turns, or 12 cards. Originally every player received 3 crew for 1-4 players, 2 for 5-6 each. Originally originally that carried on with 1 for 7-12 each, but the 'party game' version lasted until all of one conversation with Mike Hutchinson, and a personal acceptance of the unfeasibility of of 7+ players playtesting. That left a crew count of between 3 and 12 in play. Now the 3 crew single player had the heaviest playtesting, for obvious reasons, and because my game play tastes are frankly masochistic playing SSO with 3 crew is punishingly tough, but satisfyingly winnable. Opening up to multiple player playtesting it became quickly obvious that 6 crew represented a comfortable beginner level playing experience, providing 2 crew to work the hydro pods for extra oxygen and 4 to complete missions in good time. It became equally obvious that 8 or more crew made the game far too easy or far too dull. Whilst crew breathing rates increase alongside oxygen levels so the pressure remains on, Missions do not scale in difficulty well against player numbers from 8-10, leaving 2-4 crew not necessary to success, making their experience quite dull and killing them off a ready source of extra oxygen for an easy game.
This realisation led to 3 crew for 1-2 players 2 for 3, 1 for 4-6 emerging as the best numbers for game play. But SSO is a game of crew death, it is a horror survival game after all, and while player 'elimination' is a feature, eliminated players continue to effect the game by directing the Challenge Deck, but this is at best a limited form of influence.