castlevania : Symphony of the Night -> miles better even on 2D
The GOW is a mindless button hacking at the end of the day
I really understand that some of you are oldschool and firmly believe that oldschool is the best and I really respect that but to compare a 2d game to what is probably the only game to have such a large sense of scale in it and such a powerful engine is absolutely ludicrous mate.
I played Castlevania : Lords of Shadow and I liked the game. I thought the boss battles were difficult with a nice flow to it but there were aspects of the game which potrayed how lazy the game developers were. For instance, the camera angles in Castlevania: LOS is placed in such a way that you always are focusing on a narrow angle and the textures around you are of exquisite detail but If you want to explore a bit you notice that some of the textures when you go out of your linear path are really bad.
God of war beats Castlevania IMO because of so many factors.
Weapons : I really don't feel a cross is something one uses to pull of all those moves and combos. When you're using them, majority of the time it difficult for you to actually spot your weapon hitting the enemy because of the speed of the cross which really takes away the whole feeling of impact and the satisfaction of a hit in a game. In GOW, the weapons are bloody genius. Every weapon has a different combat mechanic involved in it.
Combat Mechanics : Mindless Hack'n'slash? Really? Anyone who has played the series, especially 3 will tell you that its anything but mindless hack'n'slash. You cannot beat the game with just the same combos or the same weapon throughout. The upgrades and the moves you can pull of with Kratos is really a treat to the eye compared to Castlevania where the best move you've got is spinning in one place at high speed just to notice that theres a bloody 25 hit combo that you've achieved. Im sorry mate but its in GOW and not Castlevania where you feel like you've actually killed someone.
Graphics : Castlevania loses miserably to God of war 3.
Story: I can't judge on this as I forgot the Castlevania story line

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Scale : I've seen the titan boss in Castlevania that you fight on the frozen lake. Compare that to Cronos from the God of War. Enough said really. Boss Battles, IMO I am yet to see one game that has matched the difficulty and the satisfaction that you get when you kill a boss in Hard difficulty( TITAN MODE) .
Level Design: First twenty minutes of God of War 3(poseidon boss battle).Nothing in LOS even came close to those 20 minutes at first.Enemies per screen in Lords of Shadow - 25. Enemies per screen in GodofWar3 60-75 or something. Now that's a real hack'n'slash.
Sound: I liked the sound in LOS and Gow. So its a tie for me.
There's a reason why the GOW franchise is such a hit and a success with Stig Assmussen putting in so much work in the game and making it well and truly for the fans every time they think of making a sequel. Santa Monica, easily on of the best studios around.