The base set of SSO comes with a Challenge Deck representing the ship's A.I. turning on the crew in the style of HAL in '2001: A Space Odyssey', ironic since the original basis for the shape of the game was 'Sunshine' which features a perfectly professional A.I. but gains its horror from a psychotic murderous former Captain hunting down the crew. So from original conception there were two Challenge Decks, one featuring an A.I., shutting off locations and dumping oxygen, and one featuring a murderous Captain, killing individual crew off and lowering crew's morale. But to keep retail price to £15 and distribution costs down I had to choose. Against the A.I., due to its shutting off locations crew grouping up is dangerous, but in the First Captain Deck as he stalks and kills off lone crew, splitting up is dangerous. However in the game's basic mechanics, lone crew with lowered morale are removed from the game, so splitting up is inherently risky, and useful locations need to be fully exploited by multiple crew so some bunching up is efficent. Which in short makes the A.I. deck the one with a few more finely balanced difficult choices. Additionally, the game is SSO, its named for the ship, the ship defines the look and atmosphere of the game so the first Challenge Deck representing the ship itself felt appropriate.
Still, there are fundimentally two Challenge Decks, both of which will hopefully be avalible for launch, both demanding exactly contrary responces to their challenges. During set up players are made unaware of which deck they are facing, making two decks significatly more challenging and tense than one especially since in the first two decks only 1/3 of the cards will identity your challenge, making your best path certainly uncertain, until the threat strikes.