Nintendo games were...surprisingly difficult. If you're from a later generation you may be shocked by the small number of lives and fact you often get kicked back to the beginning when you lose. Some games have codes that would display you could enter in that would let you restore to a middlepoint, and a few games had battery backed SRAM - Legend of Zelda and Final Fantasy were famous examples.
At this time, we don't have just-SRAM save/reload support. However, we do have full-state save/reload support. That means we backup the entire NES system at any exact point in gameplay. Which, I think, is a little better - just save the full game state whenever you like! You can even backup and restore your save games from a computer if you have a particularly nice game you want to keep.
Make backups of your save states! We've had one get corrupted, if you have a long game you're playing, back up the sav file on your computer.
At this time there's only one save state per game! If you'd like to add multi-file save support, we'd love to see it, but have no plans to do so
Saving is easy - hold down Select + Start for a second, and you'll get a little popup menu:
Use the joy-pad to scroll through the menu and press A to select your choice:
- Continue - means, well, continue with the game as is, no save or restore
- Save - save the current game state to disk right now.
- Reload Save - restore the game state from disk from the last time you saved, if you want to 'do over'.
- Save & Exit - Save state and quit game back to main menu
- Exit - quit game back to main menu but don't save the game state.
If you check your CIRCUITPY drive, you'll now see nes.sav files that match each game. You can back those up if you like.
Next time you load that game you'll have a new menu pop up:
Load Save Game will load the last state saved
Start New Game will ignore the save file, and just load the game fresh
Delete Save File will remove the file from the filesystem, handy when something went wrong with the save (which happens)