Lagoon Island

Lagoon Island is the fourth world in Drilling Billy. It follows Dark Cave and precedes Ancient Egypt. When time runs out, a school of piranhas swims onscreen. Lagoon Island is unique for its large bubbles, which Billy can enter and float up in.

Publisher's description
Blup! - above and below the water. The lagoon can be lovely but also dangerous. Luckily, though, above the surface Billy's safe. But too much sunbathing and he'll never be able to wet his belly - soon the piranhas will make it impossible for our little hero to do just a tiny piece of deacent [sic] work after diving into the sea. That's BAD, because being underneath the surface is precisely what's required of him to make it ahead on his journey. But as you all know creatures living in the water needs the water for breathing, therefore Billy is safe in the big bubbles floating upwards from the bottom.

Monsters

 * Conch
 * Seashell
 * Starfish
 * Chest
 * Tire