Neighborhood kitties wander in through the flap. The bubble over each one shows what it wants. Take care of them and they head home happy. Tap the door to call another kitty in.
Tap a kitty to pet it.
Muddy? Drag it into the tub.
Sleepy? Drag it onto the cushion.
Hungry? Tap the fridge, then drag a snack onto the kitty.