I'll answer what I can, most of this stuff I frankly don't know, however I can tell you that not
everything from the cinematic will be available in game.
can you use teh envirnment such as THE BUG did. as in sliding on things, sliding on your back and shooting?
I don't know about sliding backwards, but Brink allows you to slide forwards during SMART.
also when THE AVENGER stabs his knives through teh container THE BUG is in is it possible to do that in the game? as in destructive envirnments? in teh very beginning we saw someone sniping. when he goes to shoot a security a hand points and we see through the scope another sniper. is it possible to actually make someone looking through the scope change the looking? such as a "mimic" feature?
Not sure what a mimic feature is, and I wouldn't see much point in wanting to stab through a wall. As for destructable environments, Soldiers are given the task of blowing up certain objectives, such as a door for the robot to pass through in the PAX gameplay footage, but otherwise I don't think you'll be able to destroy any building like in Battlefield.
caintaner city part 1: i noticed when teh first soldier goes to place the bomb it seemed like nothing hit him. also the death animation didnt make much sense. he dropped his arms and just fell back. are death animations considered?
If you take enough damage, you don't immedietly die, you go into an incapacitated state similar to Left 4 Dead or *cough* one of the Modern Warfare games. While in this state, you're unable to shoot your primary weapon, but can shoot your secondary while on the ground if you have selected a certain "perk" (not sure what they're called in Brink), you can stay in this state indefinetly provided you're not shot, but the Medic class can give out syringes to downed players and allow them to revive themselves.
also here are just some general questions: the guns seem to be... really noobish. how will attachments affect this? i do know the system allowing you to see the stats but it seems nonone will really care about reload speed if they are just going to run around with a beast weopan.
Define "noobish".
with this i have to say something about teh S.M.A.R.T. system. i am a ps3 owner and on other titles the L3 button is usually the: move, sprint, turn button. considering this if i press L3 is all that i have to do? or is it such as Mirrors edge where there is a certain button for specific things: jump= run up a wall duck= slide under obstacles. also will ladders be incorparated? i would gladly like to know any answers i can get because iam a huge fan of BRINK.
SMART is bound to one button, if you run towards a table while holding said button down, you'll go over it automatically. You can manually jump and crouch over/under stuff if you choose, but SMART will do it all for you should you desire.
Cheers.