Cave Story/Last Cave

Last Cave (Hidden)
The last cave requires careful and difficult navigation with your jetpack 2.0

A lot of places can be bypassed with a normal jump instead of a jetpack jump, which is easier to control. Don't be afraid to just stand in a safe spot and shoot down bats for powerups and health.

Boss
There is a mini boss in the center, ideally you would have the spur for him, just dodge his shots with the jet pack and then hit him with the charged up spur.

If you still have the Life Pot, it is advisable that you save it for later, more difficult challenges. However, if you needed to use it for the boss fight, you can still return to the plantation to collect a new one.