My initial impressions are here. The main issue I had early on in playing the Medal of Honor [wiki entry - plot spoilers there] campaign was distracting audio dropouts during heavy onscreen activity, specifically when my character was firing the PKM machine gun. I'm happy to report I had no further incidents of such dropouts during the remainder of the campaign.
The only other sort of glitch I noticed is that I was able to run up onto a spawn point for the enemies in one of the later levels. I think it was in the "Rescue the Rescuers" level where you are advancing up a rocky mountain. I don't know if I moved forward too fast or just went an unexpected direction, but me and my squad were all sitting around this spawn point just killing enemies as they appeared. It took me a few seconds to realize what was happening and how these guys seemed to be getting the jump on us so quickly.
The overall narrative of the campaign is quite good, and pretty different from most games of this genre. The focus is on the soldiers and their loyalty to each other, not some overarching mega-mission to save the world. You play a number of different types of special operations soldiers, including Army Rangers, Delta Force and Tier 1 operatives, each at different points and from different points of view of the same overall sequence of events.
My favorite game mechanic is the slide - as you run to cover, if you crouch while you're running you will go into a slide and stop against the cover and end up in a crouched position, ready to go. It's really too bad this mechanic did not carry over to the multiplayer aspect of the game. The slide is a great addition that I haven't seen before, and the mechanic is executed flawlessly, much like Rainbow Six: Vegas 2's implementation of anchoring behind cover and rotating out or above to shoot (see here at about the 33 second mark).
The campaign is quite short, maybe four to six hours, depending on your skill and aggressiveness. I wish it had been longer, but what is there is good. There is a good variety of vehicle and weapon usage. The gameplay is fairly structured, however, and while you are definitely not playing "on rails," the game takes you where you need to go, providing the appropriate weapon for the situation. Also, as I have seen others mention, there are areas in the game with "invisible walls" where you can see an area your character could obviously go to, but the game simply won't let you. This sort of funnels you through some parts of the game, and while it is a small complaint and something I only noticed once or twice, it would be just that more immersive if your character could explore any area that appears accessible.
The multiplayer felt good, other than the fact that the controls did not directly carry over from the single player campaign. For one, the slide mechanic is missing, and the other thing is that your controller settings have to be set separately. For many games I don't use the default controller configuration and I had to set that configuration up in the multiplayer separately even though I had already done so for the single player campaign. Also, the configurations are named differently between the single and multiplayer, so it's not immediately apparent which in the multiplayer will be the same as what you use in single player. This is fairly small, easily remedied and hopefully a one-time thing, but I spent 10-15 seconds in my first live multiplayer map sitting vulnerable while I configured my controller.
There do not appear to be a lot of options to select the type of game you want to play in multiplayer. Admittedly, I have not played a ton of games, so maybe I just haven't found all of the options, but it looks like you select a "type" of game (combat mission, team assault, objective raid, sector control or hardcore) and go. That's fine with me, but I imagine for the multiplayer junkies out there who like specific settings, it may not be enough.
Comparisons to Battlefield Bad Company 2's multiplayer are inevitable as the same developer did the multiplayer for this game. The feel is similar, but the settings and goals in the various gametypes are different enough that I was not constantly being reminded of BFBC2. This multiplayer stands on its own. Now I just need to get some of my friends online to play with me.
I definitely give this one a "thumbs-up." The only hesitation I have in a full "buy" recommendation is that you should probably make sure your friends online are also going to buy this one since the single player campaign is so short. The campaign looks to have decent replayability with multiple levels of difficulty and a "Tier 1" mode (available after completing the game once) which involves beating each stage under a "par" time, but once that's done you'll be playing with random people online if your friends don't have the game.