Comment PC & PS1 games (Score 1) 203
Since you're willing to look at PC games, I should mention the few that I know.
Starcraft
Diablo 2
Kohan
Unreal
All of those can be set up as to-player cooperative. At the same time, the enemies in some of them are pretty dumb. Starcraft or Kohan would probably be your best bet because the strategy generally requires that you communicate with each other. My wife and I used to play a lot of cooperative Starcraft.
On the PS1, I can remember Gauntlet and Legend of Mana. In Legend of Mana, though, the second player is very definitely secondary, and not always present.
Starcraft
Diablo 2
Kohan
Unreal
All of those can be set up as to-player cooperative. At the same time, the enemies in some of them are pretty dumb. Starcraft or Kohan would probably be your best bet because the strategy generally requires that you communicate with each other. My wife and I used to play a lot of cooperative Starcraft.
On the PS1, I can remember Gauntlet and Legend of Mana. In Legend of Mana, though, the second player is very definitely secondary, and not always present.