You need to have Stanley Parable and Cheat Engine (I'll call it CE in tutorial) installed!
Step 1: Select game in steam, right-click > Properties... > Set launch options and type in "-console" (without quotations). Press Ok -> Ok
Step 2: Run both the game and the CE
Step 3: Game should have console open, type in "sv_cheats loool" (w/o quotations, you can use other words instead of loool)
Step 4: Switch (alt+tab) to CE and click on the computer in upper-left corner, select stanley.exe and click on "Open"
Step 5: Change Value Type (4 Bytes by default) to String
Step 6: Write in the largest textbox (the most upper one): "loool" (w/o quotes) and hit the button "First Scan"
Step 7: An address will appear on the left side of CE, drag it to blank space at bottom
If you get multiple addresses, choose the first one
Step 8: Click on the box (on left side, below the sign "Active") so a cross appears in it and double click on the Value "loool" (one at the bottom, below Value)


Here's a random list of fun commands for you:

• bark
  
• imabird
  
• raphael
  
• r_drawothermodels 2
  
• r_drawothermodels 0
  
• host_timescale 10 (and press "E" ingame)
  
• ent_teleport player
  
• ent_create_portal_weighted_cube

Yaay! We have go sv_cheats 1!!!
Type in "sv_cheats" to see it be 1!
But there's a sad side to it Even though you can use most commands, that require sv_cheats 1, there are a few that don't work.
They (noclip, god and a few more) will not work. But there are alot of commands that do (like the ones I gave you before)!
ENJOY!

Commands tell me to enable sv_cheats 1???
I'm not sure why it happes, but you can get past it by typing in "sv_cheats 1", getting teleported into serious room, quitting it and starting the game again!

Will I get VAC banned?
Stanley Parable does not use VAC, so no, you should not, but if something happens, it's not my fault.
But remember to close CE before playing other games and do not use this method on games like CS:GO!

But you can simply copy over demo dll file!
You can modify server.dll!
But that requires you to modify game files, my method is temporary, close game and CE and it's all back to normal!
These methods also have side-effects, ex. copying over demo dll will remove some required stuff and dll change will need to be different every update

Game dev will KILL U!!!
He will not, it's against the law! But I would like him to see this guide, I would like to know his option, I guess he'll be friendly (and patch it/turn it into a easter egg, teleport to super-serious room).
He likes having less crash reports instead of pepole crashing the game with different/modified server.dll's

...?
Write your questions in the comments!