How do you get more life in the Teenage Mutant Ninja Turtles game for Nintendo nes?

To gain extra lives in the Teenage Mutant Ninja Turtles game for the NES, you can find and collect certain items. One method is to gather 100 points, which can be achieved by defeating enemies or picking up items, as each 100 points will grant you an extra life. Additionally, you can exploit specific enemy respawns in certain areas to farm points efficiently. Lastly, if you're playing with a friend, you can also share lives with each other when necessary.