Roomstate events will not save if dying before completing.
Say you die in the pirate room after morph & missiles, you will load @ samus ship.
However, zebes will not be awakened.
You will need to go back & clear the room.

Very cheap quickfix, game will autosave @ the game over screen.
Samus will start again with max health, ammo will remain the same.
It only works with the health code in place.

$18 bytes free space in bank $82.

For your Super Metroid Entertainment System.

USE AT YOUR OWN RISK.

After further testing, this now sets you at the ship.
Plenty of time to reset while samus strips.
Is a quickfix, with some work you can get it to load last save used.

This lets you skip bomb torizo if you die while fighting...

UPDATE:
Various attempts have been made at a working autosave feature.
There's no way around events & items w/o tons of useless code.

Just saving map progress would be good enough.
Due to how the map is loading, there's no solution on my end.