 If you want something about hexadecimal and Sonic games, I highly recommend you visit the guide made by Nemesis. This is my link:<br><a href='http://pci.univ-lyon1.fr/~p0300958/SSRGguide.htm' target='_blank'>The Nemesis Sonic 2 hacking guide.</a><br>In the introduction, Nemesis explain very well how to be started with hexadecimal and Sonic editing (for Sonic 2). This is a bit boring, but very useful if you read it at least one time when you start hexadecimal. Then, you can visit also the Saxman guide to find where edit something into the rom and how:<br><a href='http://pci.univ-lyon1.fr/~p0300958/SHaCguide/index.htm' target='_blank'>The Saxman Sonic 2 hacking guide.</a><br><br>I hope this will help you a little. 