Keep the princess
A princess starts in the center of the game map, the first keeper who sends a imp to claim the tile she stands on and take her back to his dungeon will keep her. But like all princesses she is very difficult to handle, first she is manageable, but as time progresses she will be increasingly difficult to handle, her needs will go up and up; she of course wants gold, which she drains allot of pretty often, but she is also very stressful to have in the dungeon, so she will also drain mana. But this is not all she wants a proper place to live, so she needs separate living quarters, of decent quality and quantity, which of course also increases as time progresses. And finally she have a nasty tendency to nitpick on your creatures/minions all the time, and she is generally getting on their nerves. If the keeper cannot handle the princess she will leave his dungeon in defiance, and she will return to the center of the map, for other keepers to claim her. But other keepers can also steal the princess from the keeper who currently nurtures her. In the end when a certain amount of time has passed the keeper who has kept the princess the longest will win the game. If no one ever claims her, she will begin to walk to a random keeper, digging tunnels if she have to - but of course she will never do that herself her two servants will do all the hard working for her.
King of the hill
Here there is some area in the center of the map, which each keeper should try and claim, the keeper who claims the majority of tiles in the area will be king of the hill until someone else gets the majority of tiles. After a certain amount of time has passed the keeper who has been the king of the hill the longest will win. If no on has ever claimed any of the tiles in the center of the map then the keeper with the most territory will win.
Intruders
This is like Tower Defense known from WarCraft and StarCraft. You get a certain amount of gold and time to build up a set of devious tunnels with traps and doors in, then a wave of heroes enters your dungeon, walking for your dungeon temple, coming to destroy it. But be ware if you block their way by closing all ways to your dungeon temple with walls (not doors) then they will just randomly destroy you walls blocking their direct way to your dungeon temple, so you better leave them a path to walk, even though it may be filled with traps and doors. Now the player who survives the longest wins.
Take what you can and give nothing back
This is normal gameplay where the last surviving keeper wins the game. So eradicate your opponents and victory is yours.
Co-op Singleplayer
Normal run of the mill co-operative singleplayer.
All the game modes above can be played in teams of course
