In order to build the frog colony, many 'evolutions' must take place, most of which increase the number of hazards.

In Colony 1 this means the introduction of jellyfish (similar to the hydra but stay at the top of the pond), the dumping of radioactive waste (which leaves the sides and bed of the pond deadly) and finally a move to Colony 2.

This begins with the same hazards as Colony 1 but with a more complicated pond with an underwater cave area which makes swimming about more difficult.

It also acts as an extra life as if all three tadpoles are lost, the frog will reproduce before leaving with its mate for a different colony.

Colony 3 adds bumblebees which have apparently been affected by the radiation so attack the player's frog (in the only real exception to the true to life use of the rest of the creatures in the game).