The Starter Pack is a pack that is available for 48 hours after reaching level 6, when you finish the tutorial; as it is intended as a way to jumpstart your game along with your Catgame experience. It is by no means necessary and the floor does count as completed without purchasing the Starter Pack.

 

The Starter Pack is offered at levels 4, 8, 10, 12.

 

By purchasing the Starter Pack, you will be able to unlock all three starter cats:

In addition, you will receive: