I've been working on a Willow ROM hack that will implement a save game feature into a game that previously used passwords. I'm doing this just to take a crack at NES hacking, and because I read somewhere that Willow was supposed to use battery backed RAM, but instead used a password system in order to cut production costs.
I also want to implement a feature to “skip” the dialog text and also a “run” button. Source code will be freely available to help anyone else out there looking to play around with the good old NES.
Currently, I have completed my Proof-of-concept hack, and I now have a Willow ROM that allows saving current progress by pressing SELECT-B and resuming the saved game by selecting PASS WORD in the opening screen, or CONTINUE after losing all your HP.Relevant Link: