1. Open the Game, duh. Click on "RESUME GAME"

2. Wait until the game loads, and your ingame, open the console. ~

3. Type "set thereisacow 1337" without quotes and hit return.

4. Hit esc and go to "load game" remember the name of the map you are on, for example "ship-4" ignore the number, all you need is the name, in this case, ship.

5. Exit the menu by hitting esc until you are back ingame.

6. In the console type "devmap ship" without quotes but instead of ship type whatever level it said you were on in the "load game" screen.

7. The first section of that level will load, probably something you already played, dont worry.

8. Hit esc to bring up the main menu, go to "load game", and load the last level you were on (the one with the highest number after it, ex. ship-4 is newer than ship-3)

9. Load the game, cheats are now enabled on any map you load, the only downside is that any dev info will be shown, but you can enter any cheat into the console, the only one i've ever used was GOD which gives infinite health.