If you decide to play Hard Mode, the bosses are gonna attack a lot, and I mean a lot during the Megazord fights. What you need to do to avoid losing health is using the shield by pressing the L button (if your speedrunning on console) or the Y button (if your speedrunning on PC via emulator). Also make sure that you have all of your rangers powered up and have the vortex blaster with you, 'cause that does a lot of damage when doing a super attack.