hey this game will have only one sudden death. My idea is that each terrain will have its own armaggedon when sudden death happens.

armageddons destroy terrain and damage worms randomly

Samples
In hell map each turn lava missiles will destroy terrain randomly
In cheese map, alien ships will use beams to destroy terrain
In Space map, meteorites will fall
In snow map, ice shards will
In forest map, fire will start consuming terrain
(...)