Hi! Im currently in the process of text hacking "Ghostbusters" for the NES. I have changed the "Completed game" Screen, but the game is so damn hard, I cant get to it! I have tried GG codes, but none of them work. Im looking for a tool that will let me look at diffrent screens in the game (NOT A TILE VIEWER!)
Unless there's a tool specifically for this paticular game (which I doubt), there is no such tool available. "Screens" are not stored in the game in any reliably predictable manner -- each screen is drawn from the game's code when the game is run.
It's a similar reason as to why there's no universal level editors. Each level editor has to be game specific because each game stores its level information a certain way. Same thing with screen layouts. There's no telling how any game will have its screen layed out.
Out of curiosity, which Game Genie codes have you tried? If you're getting them from multiple sites/sources and *none* of them work, you might not be applying them correctly.
Once this is determined, your best bet is to hardwire them into the ROM (or a backup) with a hex editor. Then you can cruise thru the game at your leisure.