I have been playing for about 6 hours now and this is what I liked, disliked and want to see in the full game.
My specs
Graphics card: MSI GeForce N560GTX-Ti TWIN FROZR II OC overclocked to 970MHz
Motherboard: MSI P67A-GD65 B3
CPU: Intel i7 2600K overclocked to 4.2GHz
RAM: 8 Gb
First impressions
What I liked
1) Better and smother movement: I felt like I was part of the solder and in control of his movements. In arma 2 I never felt like I was in touch with the character.
2) Stance transitions: I f**king love it, nuff said.
3) Flying was easy and I didn't encounter any bugs
4) Better physics then Arma 2
5) Ran great for me: I was getting about 60-70 FPS on very high settings
6) Unusually smart animals, snakes and rabbits opening doors and fish swimming on land, I know it's a bug but it was funny.
What I don't like
1) I couldn't eject from the heli: I want to be able to eject at any time.
2) When I put my rifle from semi to auto/burst then equipped my pistol and back to the rifle the rifle was back to semi. I want the game to remember that I had my rifle on auto/burst.
3) When I was equipped with my pistol I couldn't use stance transition from low crouch to hi prone (sit), but I could wit the rifle equipped.
4) The AI wasn't all that smart but good shoots.
5) Some sounds sounded like they were taken from Arma 2
What I like to see in the full game
1) I would like to be able to shot from a heli as a passenger, for example from a MH-9 heli.
2) Stance indicator on the HUD
I still haven't thought up much to add to the full game but I sure I will think up more soon.