Cooperative play
Cooperative play is the playing of PvE together with other players.
One of the main development mantras of the Diablo 3 team was, "do no harm to co-op." and they made many changes to Diablo 2 game systems in the furtherance of this goal. Co-op improvements include:
- Individual item drops. (Players see only the items they can pick up, so no more ninja-looting.)
- No more non-consensual PvP. (No PK switch.)
- No more party system. (Players are automatically in a party together if they are in the same game.)
- Improved Friends List features on Battle.net.
While these features are definitely boosts to co-op, some fans have pointed out that they're more about the removal of anti-co-op features, rather than actual benefits to it. On that side of the coin, Diablo 3 has some areas with fewer co-op bonuses than were present in Diablo 2.
- Max players per game is lowered from 8 to 4.
- The experience gained no longer scales up hugely with more players.
- Monsters do still gain more hit points, though.
- There are many fewer shared skills in Diablo III. (Many Auras and Warcries shared in Diablo 2, while most Necromancer Curses were of benefit to all characters in the vicinity.)
- Diablo 3's quest system strongly encourages all players in the same game to play on the same quest. (This can be seen as a pro and a con as it concentrates the players in the same area, but makes it less likely that friends with much different level characters to play in the same game, but not in the same area.)
Blizzard on Co-Op
While the developers talk constantly about wanting to encourage co-op, they have very little to say in terms of actual benefits or game changes from party play. Faster killing speed from cooperation is just about their only argument. [1]
See the Multiplayer article for more details on co-op and related issues.