Go to your Library and right-click the game. Then select "Properties" at the bottom. A new window will appear with two buttons at the bottom. One reads "Set Launch Options". Click it.

You will see this popup, as shown in the screenshot, where you can enter some text.


Type:
Click "OK" to close the window.
Then close the Properties and start the game.

You will now see only a black screen with your mousecursor. On my computer it lasts about 4 seconds. Then you will see the default disclaimer page with copyright informations and quickly after the seizure warning, just like normal. The only difference is the short black screen at the beginning where the videos used to play.

Enjoy!