Every time you make the correct pattern, the game becomes difficult. The game starts easily when you have only two or three changes to make. Required changes start to increase as you progress through the game. And the real fun begins when the small grid which you observe starts to rotate.
Snowb
Bunny
Pop I
Zumb
Flapp
Cube
Stack
Vegas
Block
Tetri
Goal
Flipp
Tap T
Quiz
Speed
Green
Grass
New B
Gramm
Snack
Spide
Beach
Need
Centi
Busy
Save
Iron
Hippo
Farm
Deer
Too M
Owl J
Brick