In order things appeared in the trailer (thanks PRES_00)
SPOILER START
*Walther P99 is in the game
*HK USP45 is there too
*No ironsights as of yet Nor exanding crosshairs (just a static transparent circle)
*Hud has a zoomable digital map and a Online Contacts bar (IM/Email ?)
*Shooting a cupboard reveals that wood doesn't fragment like in HL2 tech trailer but the doors flap open and separate from the cupboard. The whole thing sways back and forth too.
*When firing at a metallic ad board, bullet marks can be seen on the wall which is on the other side therefore bullets pass through thin metal sheets.
*PB pistol with silencer is in the game (only image found here: http://legion.wplus.net/guide/army/gu/_pi.shtml
*Sofa disntegrates into major parts when shot at.
*Boar flies back when shot with a TOZ shotgun.
*PSO-1 sights can be used and looked through but it doesn't move because of breathing. The lense is dirty, which is a nice touch (is this the only realistic aiming element ?)
*The AK is an AK-74 but the weapon icon displays one with fixed wooden buttstock and the model shown on a table has a retractable one.
*Reloading sounds come from COunter-Strike mod. Is this final? A lot of people will shout Ripoff because of the familiarity of this sound.
*PSO-1 sights distance markings are not obeyed. The player always uses the top marking. Accuracy at 180 metres is accurate (player misses at that distance but not at closer range).
*Inventory Menu displays player name, player rank and community he's part of. Also, the gamer's appearance is shown in glorious 3d from the front. Different items take up different space and each item can be previewed in 3d rotational space. There is a belt and a bag in which you can store things.
*Every lving thing has ragdoll physics (very cool). A monster lands on its 4 feet and bounces off realistically.
*Boar can also displace objects and moves like it has real mass. There are no sharp turns, the animal high mass center forces it to turn with a large circle radius.
*When the player dies, information of the damage is displayed (blood drop with number 0.019) and the camera turns to 3rd person view to witness the last moments as the player tumbles.
*Explosions are also well done. After seeing the smoke when an RPG hits the ground, you have to wait a slight moment for the expanding gases to get to things around it.
*At the end it says: No one animal was harmed during production trailer production. Nice joke but they just need to employ someone who won't butcher the English language as much.
SPOILER END