I just got done playing the demo and I'm not impressed. I know that I can't judge the game on a demo that is very clearly not done. Even with that the game just hasn't impressed me.
The game looks nice. In the opening scene of the game, after Raiden lands on the beach, the water effects on Raiden are terrible. Yes it was just a demo, but the visuals looked very grainy. (not sure if that is the correct terminology)
The game seemed slow. I'm not sure how many frames it is running at but it just seemed very sluggish. I would want to turn and Raiden just moved slow, or he was slow to move.
The camera was hard to deal with. I couldn't change it and for the boss in the demo it is locked onto him. That isn't really a problem because if it wasn't he would've been much more difficult. I wish they would put some options in for changing the camera. If they would let the camera go free for the player to control that would be good too.
I was on the PS3 version of the game so I did run into some bugs. Raiden's head was glitching in and out when I was turning the camera. The game froze on me when I went into blade mode against one of the Irving. Before you kill the guy from behind you can float on the invisible platform before you jump down. You can actually jump and land on that invisible platform.
Looking past all of that though. Knowing that the game is still far from completion, I'm not impressed. I know it isn't sneaking game but they could have at least made the little sneaking that is in it good. Raiden doesn't creep forward. It is either run or walk. You don't steathfully kill the enemy from behind. Now this could change in the actually game. The situation didn't call for stealth so that might be why he didn't do it in a steathy way. Besides that, in the demo you have the option to save a civilian. If you sneak up on the guard who is directly behind the civilian and kill him, that doens't notify the guard who was in front at all. After you kill the second guard you can almost walk directly in front of the guard who is above you and not notify him either. I even cut the ground from under him and this didn't notify him of my presence. This could be seen as a bug but these are things that get left in games and they bug me.
I would also like to know why Raiden has to walk extremly slow in order to throw a grenade? Unless they serve another purpose later on in the game they slow Raiden down too much to be effective. The same goes for the rocket launcher. Either they left them in the game like this as a means to deter you away from using them and just stick to the sword play, or just another bug, it needs to be fixed or changed. If anything just take them out of the game all together, they serve little to no purpose what so ever. I only used the rocket once and that was to see if the thing actually worked. Still don't know if the grenades do. I tried to throw one and got kicked in the face by Irving.
I've digressed from the ending of this post. Even after looking past all of this and focusing on what the game is supposed to do, it doesn't impress me. I'm not really interested in the story anymore. I can tell that it isn't coming direclty from the mind of Kojima. I can tell this from conversation and the inconsistency of Raiden's actions from the beginning to what he says to the prototype. It also seems somewhat tacked on about getting enemy electrolytes and arms. Just put into the game to give the player a reason to chop up the enemy. Hopefully in the full they explain why he needs to recharge in that fashion. I also hope they give a good reason as to why Raiden decided to fight again. Just saying he works as protection and he got involved isn't enough. If he is fueled by revenge then it needs to be aparent. The beginning of the demo shows this but the end shows something almost completly different. I would have been ok with this but it was too different from Raiden in the beginning and it was a completly different personality from what he have seen before.
Just rating this game from the demo I would give it a solid 7. The game works but it doesn't do much after that.