About saving games

Saving a game is possible in two ways, and they tend to confuse new players. This article tries to clear this up

SRAM and savegames

This is the official way of saving your progress offered by the game/platform

Some platforms and games support saving your progress. Often, this is stored inside of the game cartridge. More modern systems use flash memory, but older systems used static random access memory (SRAM), a type of memory that can be rewritten fairly quickly as often as desired. For the data to remain, a battery is used to continuously supply the small current required to keep the data intact. If you have a game that no longer saves, you likely have a dead battery.
Just because a platform supports this functionality doesn't means the game does too. A famous example is Tetris® for the Nintendo® GameBoy®. The platform supports saving your game, but this specific game doesn't.

How it is saved

The emulator watches over the SRAM region, and if it detects a change, it takes a copy of the memory, and uploads it to the server if you're logged in.
When you play the game at a later point, the data is loaded again from the server and restored.
You need to be logged in for this to work

Save states

This is an unintended way of saving, offered by practically all emulators

Old platforms are fairly simple to emulate, and don't require a lot of memory. Save states use this to their advantage.
When you create a save state, the emulator is briefly frozen in time, and the entire state of the emulated hardware (processor, memory, audio, etc.) is saved to a file.
This file can later be used to restore the emulator to the exact state when the snapshot was made.

Saving a game this way brings huge benefits, among them:
It's a lot faster than SRAM based saving.
You can save your progress in games that don't support saving.
You can save before a difficult part and then repeatedly retry said part.
You can redo luck based sections until the random number generator acts in your favor.

How it is saved

When you click the floppy icon in the emulator menu, a state snapshot is taken and sent to the server.
When you come back later, the state is automatically loaded when you start up the same game again.
You need to be logged in for this to work

SRAM vs Saved state

If you happen to have both, an SRAM file and a saved state, the emulator will prefer the saved state over the SRAM.
You can delete an unwanted state from your save game page.