Play as Iceberg (an iceberg) on it's hunt for Pipanic - the most majestic cruise liner in the world. But you know what they said about this ship? It would be unsinkable. Quite. So, yeah, it's pretty strong! And in order to sink it, Iceberg has to become strong enough before it should attack it.
Ram small ships to gain experience until Iceberg reaches level 20 - when the Pipanic will appear. Your time to sink it.