Dungeon Keeper is a hard game to review. That's because any critique of this remake of Bullfrog's 1997 PC hit can't help but slide down the slippery slope towards being a critique of free-to-play gaming in general, and that's when people start banging the table and raising their voices and it all goes a bit Jeremy Kyle.
It is, at least, easy to see why EA revived this beloved cult classic in this fashion. Revisit the original Dungeon Keeper today and be amazed at just how many of its ideas have been reborn in mobile games. It was one of the first "tower defence" games, for example, flipping gaming convention upside down by casting the player as an evil tyrant, crafting the most perfectly evil lair in which to trap and kill do-gooder enemies who enter your hallways looking to save the world.
You did this by using an expanding army of imps to dig out new rooms, which you could then use to house traps, treasure and monster-spawning hatcheries. The more you expanded your labyrinth, the more stuff you discovered. The more stuff you discovered, the more new things you could build. It was a near-perfect feedback loop of routine and invention.