The mother ship is in danger and needs a certain item collection to make repairs. The players - ship officers - are sent to collect the items.
If no one brings back a collection within X rounds, the ship experiences catastrophic failure. Anyone who brings back at least a workable collection receives a service award. The person or team who brings back the best collection will also receive bonus vacation privileges.
What would happen if I left the rules like that?
My feeling is that most anyone who sees the rules like this is expecting a final sentence or two: And the winner is the person who brings back the biggest collection. Or: the game is a cooperative game where you score for the number of players that win. Or: play with teams. Or: each player gets a goal card: the player wins if every player gets a complete collection, or if only he has the best collection, or he is a traitor, and so on.
If played entirely cooperatively, bringing back a collection to save the ship will be challenging. If played entirely competitively, one person might be able to bring back the collection and prevent everyone else from doing so, but this vastly increases the risk of catastrophic failure. You may find yourself unable to win, but able to prevent anyone else from winning. It could be played as teams. Or once one person has a collection, they could help everyone else get their collection.
Do I have to add anything about winning? Can I let the players decide for themselves if they want to play cooperatively or competitively or half and half or with teams? After all, in the real world situation this is simulating, the actors get to decide this for themselves. Is the story of the game sufficient motivation for the players; or does there have to be a defined concept of winning and/or losing?