Before starting the game, go to the shortcut to the game executable, right click it, tap properties, and then change the target path to the file with the additional parameters:
+set cheats 1 +set ui_console 1 +set thereisnomonkey 1.

If this doesn’t do the trick, you can take into consideration changing it to:
+set developer 1 +set ui_console 1 +set cheats 1 +set thereisnomonkey 1.

To get to the core of things, read: cheats, you must first press the tilde key “~” and get the console window to show. Herein you can introduce any cheats to your liking, but keep in mind that they only work with version 1.11 and lower. You can also type in “+set cl_playintro 1” if you wish to see the introduction sequence. These codes are meant to be used in single-player games only, but they will also work in multiplayer games if the server or host has specifically enabled them.


Cheat Codes

dog - God Mode
fullheal - Full Health
wuss - All Weapons & Ammo
noclip - No Clipping (Go Through Walls)
notarget - Invisibility
tele x y z - Teleport to Location X Y Z
coord - Show Current Location
listinventory - List Inventory
kill - commit suicide
gameversion - Show Game Version
toggle cg_3rd_person - 3rd Person View
maplist - Generate List of Maps
map [map name] - Warp to Level
giveweapon weapons/''weapon_name''.tik - Give Weapon


Weapon List

colt45
silencedpistol
webley_revolver
nagant_revolver
sten
springfield
thompsonmsg
ppsh_smg
bar
enfield
g43
mp44
kar98
kar98sniper
mosin_nagant_rifle
svt_rifle
p38
m2frag_grenade
steilhandgranate
nebelhandgranate
mills_grenade
russian_f1_grenade
rdg-1_smoke_grenade
m18_smoke_grenade
bazooka
panzerschreck
shotgun
mg42carryable


Map Names

Single player
t1l1, t1l2, t1l3
t2l1, t2l2, t2l3, t2l4
t3l1, t2l2

Multiplayer
m1l1, m1l2a, m1l2b, m1l3a, m1l3b, m1l3c
m2l1, m2l2a, m2l2b, m2l2c, m2l3
m3l1a, m3l1b, m3l2, m3l3
m4l0, m4l1, m4l2, m4l3
m5l1a, m5l1b, m5l2a, m5l2b, m5l3
m6l1a, m6l1b, m6l1c, m6l2a, m6l2b, m6l3a, m6l3b, m6l3c, m6l3d, m6l3e