You first need to get to 3-X. (One Shift More) (i don't know if you need to beat the level first before unlocking the hidden level.)

In Paige's Room, there are faint arrows on the wall. They tell you which keys to press, but if you can't see them, these are the directions. (you need to start in paige's room)

> < > > < > < < > < > > < > < <

Upon inputting this sequence, the level will start. It's One Shift More, but with dogs.


Fun fact: If you pause the level, paused will be replaced by pawsed, continue with fetch, restart with again, settings with stuff, and quit with bye.