Multiplayers games such as Stardew Valley are largely player-centric and depend on the environment in which people play them. Whether the players are playing the game in the same room or at a distance changes how players interact with the game. Last Friday, since the class was split into four groups and played together in the same classroom, I observed multiple characteristics that wouldn't have occurred if the players were playing independently.
First, each group often looked at other groups' screens to see what they were doing. For example, when my group was walking through a tunnel, another group was intrigued and asked where we were. After we told them we were at a tunnel to the left of the bus, a third group jumped in and told us that the tunnel would lead to a desert and continue walking down the path might be a bad idea. Therefore, our group stopped and went back. As you can see, there is a learning process between the groups. One looks at what another group is doing and finds out what he can do in the game. In a way, when multiple players are playing in the same room, they operate as a larger whole--whatever one player discovers is soon discovered by other players. For example, when the group next to mine found that one can fish by the pier, my group immediately tried it as well.
Second, it is easier to enforce cooperation among the groups. Since the players are all in the same room, communication is fast and convenient. Thus, it is easier for players to monitor other people's actions, impose blame, and keep each other in check. For example, there was this one time when all players but one have already gone to sleep. However, the one person is still outdoor and stops the game from going into the next day. Soon, all the people in the class found out who that player was and ushered him to go to bed. Under everyone's pressure, the player soon abandoned what he was doing and went back to his house so that everyone else could advance into the next day. Therefore, when players are playing in the same room, their gameplay is more easily influenced and bound by others'.
I found this co-op game to suffer most from these actions that require all 4 players to complete (going to sleep). It is at these moments that players are most tested especially taking the mounting consequences of falling asleep and losing further energy for the group. I see it as the ultimate reseting barrier that would take the compounding work of the day done by players and challenged them based on it. In other words, depending on how well you work during the day, and how much you get done efficiently, the higher your chances of surviving another night without severely punishing your fellow players.