At the beginning of the level, jump on then off the trolley-like object as fast as possible and run down the path. There should be structures coming out of the ceiling when you reach the bottom. The first has a mechanical bat enemy and the second one has bat-like enemy that looks real. Also kill the flamingo enemy. When you kill the realistic bat, almost every time it dies it will drop an extra life. Run back to where the second structure on the ceiling is off screen, then run back and kill it again. Keep repeating this process to get as many lives as desired.