Codes for over 100 games are included in the accompanying book.
Quarterly code updates can be ordered for $3.50 + 1.50 S/H. The
Genesis Game Genie allows up to five codes to be used simultaneously,
but some effects require two or more codes.
Games I have tried the GG with include Toe Jam & Earl, Quackshot,
Streets of Rage, Spiderman, and Sonic. One of the most useful codes
(IMHO) is the TJ&E 'short game' code. This code causes all of the ship
pieces to appear in the first eleven levels.
I hope that this doesn't deteriorate into a flamewar regarding the use
of such devices, cheats, etc. One observation I can offer is that the
Genesis GG also includes codes to make games _harder_. To use TJ&E as
an example again, you can make all the enemies appear as boogiemen or
moles.
If you have questions about specific games, e-mail me. The box that
the GG comes in does not list the games with codes included.
Enjoy!