The DLC will does not affect really affect the game, but you can consider purchasing it if you like the game.

This DLC includes:

• A cheating method to skip the current level
  
• A real commentary track
  
• Some art and audios related to the game
  
• Some irrelevant cat pictures that may make you smile

Note:

The aforementioned cheating method is available without the DLC.

How to Get:

You can find the files in the game folder once you've download the game.