The following guns can be seen in the upcoming video game:
Handguns
Beretta M9
MP412 REX
Colt M1911
MP-433 Grach
Beretta M93R
Submachine Guns
IMI Uzi
M1928 Thompson
M1928A1 Thompson, .45 ACP
PP-2000
Heckler & Koch UMP45
Heckler & Koch UMP .45 ACP
Assault Rifles
9A-91
Heckler & Koch XM8
Heckler & Koch XM8, 5.56mm
Heckler & Koch 416
Heckler & Koch HK416, 5.56x45mm NATO
AEK-971
AN-94
AKS-74U
M16A4
M4A1
Though it is not yet known whether this will be in the game (likely not) it is the weapon being held by the soldier on the game's cover art.
Steyr AUG A3
FN F2000 Tactical
FN F2000 Tactical, 5.56x45mm NATO
FN SCAR-L
Heckler & Koch XM8 Compact
Heckler & Koch XM8 Compact, 5.56x45mm
Sniper Rifles
QBU-88
SV-98
SV-98, 7.62x54R/7.62x51mm NATO
VSS Vintorez
M14 EBR
M24
M24, 7.62x51mm NATO, .300 Winchester Magnum
Barrett M95
GOL
SVU
Shotguns
Remington 870MCS
Remington 870MCS, 12 Gauge
Franchi SPAS-12
Franchi SPAS-12, 12 Gauge
Franchi SPAS-15
Franchi SPAS-15, 12 Gauge
NeoStead 2000
Neostead Shotgun, 12 Gauge
Saiga-20
TOZ-194
USAS12
Machine Guns
M249 SAW Paratrooper
PKM
Heckler & Koch MG36
Heckler & Koch MG36, 5.56x45mm
XM8 LMG
QJY-88
M60
MG3
Launchers
M203
GP-30
Heckler & Koch M320
Heckler & Koch M320, 40mm
FN EGLM
RPG-7
M136 AT4
Carl Gustav M2
Emplaced Weapons
XM312
Kord
Kord heavy machine gun 12.7x108mm with ammo drum
M134 Minigun
Dillon Aero M134 with flash suppressor - 7.62x51mm. These are new model M134 Miniguns or just updated GE Miniguns which are usually seen with a different spade grip mount that were used during the Vietnam War.
BGM-71 TOW
BGM-71 TOW tripod-mounted
AT-14 Kornet