What are the differences between a 2-cycle and a 4-cycle engine in terms of their performance and efficiency?

A 2-cycle engine completes a power cycle in two strokes of the piston, while a 4-cycle engine completes it in four strokes. 2-cycle engines are simpler and lighter but less fuel-efficient and produce more emissions. 4-cycle engines are more complex but offer better fuel efficiency and lower emissions, resulting in better overall performance and efficiency.