cheat programs

[Phantom_RAcast]

who cares? (roms are illegal and they are around)
let me simplify this question
let's take for ex the sonic 1 for genesis
wich program did they use to make the game?............
a rom hack program is similar , i change the necessary stuff (red sonic, green water..........) and the rest of the game stays the same (no cheats are involve)
now pso , wich program(s) did sega use to make the game?
i want the same or a similar one to change the game just for me
the game stays the same exept for some minor stuff.

They used a compiler, what your asking will never ever happen. Ever. Rom hacks if I'm not mistaken modify memory which is the same thing as using a cheat.