[devindotcom]

If you're interested in doing this yourself, you don't need a separate hex editor; FCEUX has one built in:

http://www.fceux.com/web/home.html

Hex value watching and editing is a valued tool in the time attack community. If you advance frame by frame and watch certain values, you can see patterns showing when an enemy will attack, an item will drop, etc. Time attackers use it to minimize the time spent waiting for enemies, or finding which character actions affect level or enemy patterns.

http://tasvideos.org/Glossary.html#HexEdit

http://tasvideos.org/InputFileEditing.html

[dmm]

emacs also has a hex editor built in called hexl mode. To use it just use C-x C-f to open a file and then use M-x hexl-mode.

https://www.gnu.org/software/emacs/manual/html_node/emacs/Ed...

[Natsu]

I bet someone could make it into a Gameshark code.