You can simply creat a new profile in the base game with the folloing name 2ndsquad to unlock all the extras in the extras menu. cheats/movies will all be unlocked for you in the game withought having to actually earn them by finishing the game it self.

Beware the folliwn steps involves editing a .ini file, Always make a copy of said file in case you mess something up by mistake!

Additionaly you can look for the a file called EIN.ini in your game folder, open it with notepad
press ctrl + f key in your keyboard and browse for Consolekey=0 in the EIN.ini file or you could try and find it manualy if you wish
Onse you found Consolekey=0 change the 0 to 192

it should look like:
Consolekey=192

{We are basicly changing a key bind so we can open the game dev console in game so the 0 key is none and 192 is the ' key next to the 1 key in your keybord}

Now that we assigned a key for the console command we actually need to enable the console in game press Ctrl + F again and search for "bEnableDebugConsoleAndMenu=False", again you could try and find it manualy it should be somewhere near the bottom of the .ini file

Now change the False to True
it should look like this:
bEnableDebugConsoleAndMenu=True

Save(Ctrl+S) and exit the EIN.ini file

Launche the game
We're all set
Now... i'll provide a list of CCs for you guys
A reminder that you can press the " ' " key next to the " 1 " in your keyboard to open the console in game to use the folloing console commands.

Type on the console ONLY the commands on the Left before the dots!
Cheat Effect
fly .............................fly around
noclip .......................Fly through walls/Ground/objects
supersquad .............Gives Your Squad Infinite Health
god ..........................Godmode
loaded .....................Lots of Ammo
allammo ..................Lots of Ammo
oldmovie ..................play game in black and white mode
walk .........................return to normal walking
allweapons ..............Start Level With All Weapons

Weapons cheats insert these in the console to gain the speciffic weapon you want
some may not work.
Cheat Effect
gbxInventory.PickupWeapUSBar .................Gives BAR
gbxInventory.PickupWeapUSBazooka .........Gives Bazooka
gbxInventory.PickupWeapUSColt1911_ ........Gives Colt1911
gbxInventory.PickupWeapDEFG42_ .............Gives FG42
gbxInventory.PickupWeapDEFG42Sniper .....Gives FG42 with scope
gbxInventory.PickupWeapDEK98Sniper ........Gives K98 with scope
gbxInventory.PickupWeapDEK98_ .................Gives KAR98
gbxInventory.PickupWeapUSM1_ ..................Gives M1
gbxInventory.PickupWeapUSM1Carbine ........Gives M1 Carbine
gbxInventory.PickupWeapUSM3A1_ ..............Gives M3A1
gbxInventory.PickupWeapDEMP40_ ..............Gives MP40
gbxInventory.PickupWeapDEP38_ .................Gives P38
gbxInventory.PickupWeapDEPanzerfaust .......Gives Panzerfaust
gbxInventory.PickupWeapUSSpringfield .........Gives Springfield
gbxInventory.PickupWeapDESTG44_ .............Gives STG44
gbxInventory.PickupWeapUSThompson .........Gives Thompson

You can also ajust the FOV as you want the cc for it should be FOV followed by the desired value

exemple:
FOV 90

this will set the players field of view(FOV) to 90
also you can use the command Behindview 1 to play in third person tho its kinda hard to aim i dont recommend it and behindview 0 to play in first person again.

do Please try to finish the game in a legit way at least once
i provided this guide for those like me who just want to have fun and blast the enemies to small bits lol
have fun!