A radical departure from the rest of the Kingdom Under Fire series, "Kingdom Under Fire: Circle of Doom" changes the series from a RTS game with some hack-and-slash elements to a pure hack-and-slash.
First, some history: Kingdom Under Fire started as a PC game that was basically another Warcraft clone. Later, it moved to the Xbox with KUF: Crusaders and KUF: Heroes, which had a really unique system - most of the time it was strategy, used from a third-person perspective from your different platoons, but when you got into melee with your leader's group you would take control of your leader and hack-and-slash your way through the crowd. This helped you win battles that would otherwise find you outmatched.
In Circle of Doom, the series has moved entirely to that Hack-and-Slash mechanic. There are six characters, all of whom are from previous KUF games (4 from the Xbox titles, and 2 from the original PC one). These characters differ in their speed, their strength, and the types of weapons they can use. In the beginning, five characters are available, with one more being unlockable. Their storylines mostly revolve around their disappearances at the end of their respective games - now they are in a new realm, devoid of humans besides themselves. The only characters in the "real world" are the three idols that you encounter at rest points. These act as the game's merchants, selling you different gear depending on which idol is there (the bubbly Idol of Love, the dark and shrouded Idol of Death, and the Buddha-like Idol of Greed.) Furthermore, you can fall asleep at rest points, and in your dreams you will be transported to the Realm of Darkness, a subdimension that holds the dead spirits of the game's other characters. These spirits are also recognizable from previous games. They assign quests, teach abilities, and provide general story information. Other than those two minor sources, there is almost no story or interaction in the game.
The gameplay should be at least the redeeming part to the game, but for the most part it's not. Swinging a weapon requires "SP", or "Stamina Points", which recharge naturally. This means that most of your hack-and-slash actions will be punctuated by waiting for your stamina to recharge. This really takes you out of the game and is downright frustrating most of the time. There are lots of magical abilities to be learned, and this requires not just leveling up but also doing quests (most often "kill X number of this type of enemy"). For the most part, the gameplay lacks a lot of the combo attacks and excitement that the Xbox games held in their hack-and-slash sections. It's also possible to do a co-op mode with up to four people over Xbox Live, using head
The graphics are without a doubt the game's best part. The characters - friend and foe - are all really detailed and textured, and all the effects are really fantastic. The lighting, especially, looks fantastic. The environments - including a forest, a ruined city, and an underground area - are all rendered impressively, with lots of little details and side parts. Blood - which can be turned on or off - is shown as artistic sprays of color. The music is also very haunting and beautiful, conveying the sense of a dead, empty world. The voice acting isn't great, but it comes up so infrequently that it doesn't matter.
As a whole, this game has a lot going for it (the graphics and the co-op option being the main two) but also a lot more not going for it (the gameplay, the lack of story, the comparison of this game to other KUF games). Even as a hack-and-slash, it's not a whole lot of fun. It seems like a lot of wasted effort on the parts of the development team.