There's a great feature in the Atari 2600 Emulator, Stella that makes it a snap to go backward in gameplay. If you get injured, loose a life or just want to make a different decision earlier in the game, you can use the Time Machine to roll back the clock and find the exact spot you want to resume playing.
The Time Machine eliminates the need to mash your F9 to save a point in the game, then press F10 to move to the next save point and then F9 again to save further progress. Time Machine will automatically save your games progress so you can simply scroll back and forth to find that specific spot you need.
For complete instructions and a walkthrough
watch the video below