The Best Ending isn't incredibly difficult unless you (like me) are playing at 3 Health.

However, unless they felt like being callous, it shouldn't have an impact (considering you can access the Best Ending in other alternate game modes as well). I will say up front that I don't think that Easy difficulty affects this, but I've only played the original. What is it I must and, most importantly, must not do to get the best ending?.Is this path even available at all on Easy difficulty, what I'm playing on?.Do I want to get the best ending, or is it something so incredibly hard (think 'I Wanna Be The Guy!' difficulty) that's best left ignored pretending it doesn't exist?.He didn't even ask me if I wanted the stupid booster or not. This will cause you to lose your chance to get the Booster 2.0 later, and also keep you from getting the best ending, but it will allow you to use the Booster 0.8 to reach the door to the room with the Arms Barrier. Go ahead past Monster X, talk to Professor Booster, and get the Booster 0.8.If you have the Machine Gun on level 3, boost upwards by firing it down.There are several ways to get to the door: I was in Labyrinth B, looking for a power source of sorts, and I thought I'd done everything there needs to be done in the general neightbourhood, zealously saving after each event. Well, five minutes ago I got stuck for long enough in Cave Story+ to finally fire up a walkthrough for the game. It's very difficult to explain without any spoilers, but it involves skipping certain events and items to get better items at a later point, and making sure you follow through on an optional sequence of events. The best ending is achieved by following specific requirements at certain points in the game. Grace Note said, in an answer I hadn't read until it was too late:

Cave story best ending