Since it is rarely known to most people I figured I should write how to use cheats in game multiple times. It works for all graphics versions of the game for Windows Vista, Windows 7, Windows 8/8.1, and Windows 10 users.

Right click on one of the shortcuts for MDK (ie "MDK (3dfx)" ) and click on properties.

Add the following command line perimeters to the shortcut target box (contains the path to the executable file) 1 space after the quotation mark on the end:

" -anythinggoesG" (with the space but without quotation marks (and yes it is case sensitive):

Then on the main levels (the non transitional levels...ie tunnels and free-fall sequences) type the following:

Dummy decoy: dum
World's most interesting bomb: wmi
World's smallest nuclear explosion: nuk
Thumper: thu
Tornado: twi
Tornado: tii
Hand grenade: hbo
Bones airstrike: bon
Super chain gun: gat
homing bullets: hom
Sniper grenade: sgr
Homing sniper grenade: hgr
Mortar: lgr
Gunta snack: sea
Finish world, advance to tunnel sequence: end