Ok, some impressions.
Controls
Controls are actually fairly good. And considering all console FPS should be burned and ported to PC, that's good. Controls are setup as follows:
D-Pad Up/Down: Cycles between views. From down to up: 3rd person, 1st person, zoom (scope/binoculars)
D-Pad Left/Right: Lean to the side
Left Stick: Walk, strafe
Right Stick: Turn, aim
L3: Change rate of fire (single shot, burst, automatic)
R3: Reload
X: Appears to be action button
O: Talk/give command
Triangle: Cycle through positions (standing, crouch, prone)
Square: Jump? I have jumped, not exactly sure how anymore
R1: Fire
R2: Change weapon (list pops up)
L1: Not sure
L2: Seems to switch to my handgun
Now my complaints. L2 seems to autoswitch to my handgun. Why do I want that? I am hoping it's possible to determine which gun you can switch to. I would much rather have it switch to a grenade quick, or something like that. It's a demo, not everything is available.
Aiming is kinda hard. Even when zoomed in through a scope, it's fairly difficult to line up your shot quickly, and accuratly. They said the game won't allow keyboard/mouse for controlling your player, and I can see why. Aiming on PS2 is a real handicap. Out of the zoom, it has like an auto-aim feature. Beats me how it works. It sure doesn't snap to position like goldeneye. I think you may just be able to shoot close to them, and his them. In a scope view, you need a dead on shot for sure.
Graphics
It's a PS2 game, can't expect much

But really, the game looks nice. No complaints from me. Although I am running it through S-Video, and I did notice that it had an option for 480p progressive scan. To my knowledge, Ps2 doesn't even support progressive scan, or maybe it doesn't have a progressive scan chip and needs to put it directly on disc. I don't know. All I know is I'm gonna run out, grab some PS2 component cables, and hook this bad boy up for some better graphics. Only reason I use S-Video now is cause I switch between 2 component video slots, with Xbox, DVD, and Gamecube. Adding another would be torture, but for SOCOM, I'll do it.
Gameplay
Wordalicious! Actually, this game kicks major ass. But it's playing too much like a FPS right now. It's a demo, you're not even supposed to have a clue what you're doing. But I wouldn't even give SOCOM a second look if it was just a FPS. I wanna get into the tactics part of the game. I want the enemies to sneak up behind me cause I was being stupid and left footprints visible. I wanna sneak around in long grass. But can you imagine walking into a store, playing a demo from a game you've never played, and not be able to win without a lot of patience, and strategy, and stealth? I think this would make a far better demo, but all it does is leaves me wanting more.
Reloading, I must give them credit. You may have noticed there is a reload button, but they made it good! You get 3 magazines. If you're down to 7 bullets in one, hit reload and you switch to another. Get down to 15, hit reload and you're on your last one. Get down to 3 bullets on that one, hit reload, and you're back to you're magazine with 7. You don't just magically fill up the remainder on the magazine like in most FPS.
Also, you get primary and secondary objectives. You don't need to do any secondary objectives to complete the mission. So I'm wondering what will really become of it in the final game. In the demo, I am able to avoid like 5 buildings by not doing the secondary objectives. Interesting.
Anyway, I don't want to comment too much on the gameplay. This game isn't final, it's mostly pick-up-and-play. I have figured out where the locations are to order my men, but I still have seem no real reason why I want to put them there. Strategy has really played no part in this demo so far. It plays just like a counter-terrorism FPS would. But that's not what makes SOCOM special. If the final version was like the demo, I would pass it up for Counter-Strike. But I know that strategy is a big part of the game, and I understand that it wouldn't make for a good demo. So all I can do is try to master my SOCOM skills, and wait for the final version.