This was originally created to enable debug mode in Sonic ROM's. It has been greatly enhanced now and supports several other editing features to configure a savestate exactly how you want it. This program can edit Sonic Spinball savestates and allow you to change the players status such as lives and score. This tool is very useful. This program is a simple, fast, and very small console-based program which will enable debug mode in the specified savestate.
Most people aim for editing savestates.
This program does something related, but in a different way. This program will edit the RAM while you have the game running. You can edit how many rings, lives, emeralds, etc that you have. Here is the text editing tool that was used to help create the Sonic 1 beta hoax. It simply finds the searched string and changes it to whatever you want.