Keep in mind that as you Lewis and Clark your way across this strange overworld your dungeon keeps working in the background. You can swap back and forth between the two views instantaneously by clicking on either of the two respective mini-maps. Even so, it's an almost overwhelming amount of stuff to pay attention to--you might switch to your dungeon to construct more troops only to switch back to the top layer and find your existing orc army in a heated conflict with a half dozen knights.
There are also times where you're forced to explore underground--helping the Naga, for instance, requires you to recover a valuable mana stone from an old abandoned base. Going underground returns you to the original Dungeon Keeper style of interaction, disallowing direct control of your troops. The same applies when the forces of good come and invade your realm.
It's an interesting and stressful blend of two different game types, and definitely feels like a step up from the original Dungeons. I'm particularly intrigued by multiplayer, where four players will start underground and then battle it out on the overworld map. Provided developer Realmforge gets the balance of various units right, it could make for a pretty wild multiplayer game--you wouldn't know what you were in for upon invading another player's dungeon until you were already down there, and by then it's too late.
Look for this one in early 2015. It's already looking way better than EA's crappy free-to-play Dungeon Keeper sequel.
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