Making Game Genie's SNES codes out of random letters and numbers
If you already have at least one code for your game, you can dramatically improve your odds of finding new codes at random. First, however, it will be assumed that you do not already have codes for the game. (If you did, you'd probably start by changing those!) As with NES codes, there is only one major restriction on what you enter. Older, smaller games--technically known as LoROM games--must not use certain characters in the third slot. Look at the characters available:
D F 4 7 0 9 1 5 6 B C 8 A 2 3 E
If you are working with an older game, you must use a character from 6 to E in the third slot. For larger, newer games, you can use anything you want.
If you do already have a working code, it helps to give new random codes a similar structure. A good place to start is to use the same third character. For example, every single code for Mega Man X save for one has a 'B' in the third slot. The odds of new codes working increase dramatically when you do the same.
Another important part of the code is the entire second half, characters five through eight. The following information comes from Aerostar's SNES GG Handbook, available from the GGCCC file collection:
Char. 5, 7 Char 6, 8
D 0 6 A D F 4 7
F 9 B 2 0 9 1 5
4 1 C 3 6 B C 8
7 5 8 E A 2 3 E
The secret is to pick each of the last four characters from the same row that the old code's character comes from. For example, you already have a code that ends in D0A7. Character 5 comes from its first row, so your code's fifth character can be D, 0, 6, or A. Character 6 comes from its second row, so your code's sixth character can be 0, 9, 1, or 5. Character 7 comes from its first row, so your options are the same as for the fifth. Character 8 comes from its first row, so your code's eight character can be D, F, 4, or 7. By selecting characters related to those that have worked before, your codes gain a better chance of working.
Another way to make new codes more effective is to choose the right two characters at the beginning. Although there is no scientific rule regarding what you have to put in the first two slots, certain combinations more often have an effect. EE is good at both making the game crash and at keeping the game from crashing. If you just want to see if a code has any potential at all, it is a good idea to start it with EE. A friendlier combination is DD, which can often make crash codes better behaved. Another safe start is 3C. Finally, if you want to go for the gold, try some codes that begin with C, particularly with C2, C4, or C9. If you look at "Infinite somethingorother" codes in the codebook, you will find that most of them begin with C.
