Catherine has four difficulties, each with slightly different rules. Though difficulty is set in the beginning of the game, it can be changed at any point in the Stray Sheep by accessing the Config menu of Vincent's phone. Note that some achievements and game modes can only be unlocked on certain difficulties.

Very EasyEdit

This is the only difficulty not actually selectable on the main menu by default. To play on "Very Easy", hold down the Back/Select button for a few seconds on the main screen (highlighting "Golden Theater"). After you hear a tone, select 'Easy' mode, which will now be Very Easy. You can switch between Easy and Very Easy as much as you want during the game.

• "Very Easy" comes with the capability of undoing your last move (up to 10 times) by pressing Back/Select during the level.
• This mode's Nightmare levels are the same as "Easy".
• Collecting a Mystic Pillow grants you 3 retries.
• Safety Bonus score multiplier of 2.0
• Power Drinks have a high chance of showing up on top of any block you pull out. These are more powerful versions of Energy Drinks, and allow you to climb 3 blocks at once for a limited time.

EasyEdit

• "Easy" comes with the capability of undoing your last move (up to 10 times) by pressing Back/Select during the level.
• This mode's Nightmare levels are the same as "Very Easy".
• Collecting a Mystic Pillow grants you 3 retries.
• Safety Bonus score multiplier of 2.0

NormalEdit

• "Normal" comes with the capability of undoing your last move (up to 10 times) by pressing Back/Select during the level.
• This mode's Nightmare levels are slightly different than "Easy", and more difficult.
• Blocks fall slightly faster in this difficulty.
• There is less time to keep up the chain step counter.
• Collecting a Mystic Pillow grants you 2 retries.
• Safety Bonus score multiplier of 1.5
• Certain Achievements are only possible on "Normal".

HardEdit

• "Hard" does not come with the ability of undoing your last move.
• This mode's Nightmare levels are different and far more difficult than "Easy" or "Normal".
• Blocks fall quite a bit faster in this difficulty.
• There is less time to keep up the chain step counter.
• Collecting a Mystic Pillow grants you 1 retry.
• Safety Bonus score multiplier of 1.0 (none)
• One achievement is only possible on "Hard".