Co-op game - suggestions?

[traen]

After playing Gauntlet Legends for Dreamcast with my friends, I'm now looking for another game that is also co-operative. That is, one that you can complete missions/tasks together with up to 4 players, all on the same Dreamcast console.

Lay 'em on me.

[Megalith]

There was Zombie Revenge. I think you could play with up to 2 players only though.