Edit : for a good example of the sneaking mechanics, i simply searched "deus Ex Metal Gear Solid" and found this cool video, you can see the stealth mechanics
watch those two video then continue reading!
http://www.youtube.com/watch?v=H55ogeygo9I
http://www.youtube.com/watch?v=Hx-YbUO9Ec4&feature=related
This game is soooo good, but i can see MGS fans loving it, it got the stealth, interactivity , awesome bosses, ventelation ducts.... LOTS OF THEM, lots of radio chatter and all the attention to detail you'd expect from an MGS game , plus much more. (like choices and non linear gameplay)
if you are an MGS fan, trust me! , this game is going to make you a very happy panda.
so in short
Gameplay = Awesome
Immersion = You really feel like you are in this believable world, everything in it feels natural , its not sci-fi where impossible things happen, its the future of today's world , not post apocalyptic , nor very fantasy.
Soundtrack = one of the best i've heard
Artstyle = very artistic (this sadly can't be seen from the trailer that make it look so black and gold) , every clothing , geomatry and adverts ...ect ect , has a unique but believable style to it.
Characters = very well done, and the main character is a badass although NOT a generic badass, he actually feel human.
