If you have programming experience you already have an advantage over many other people who have come in the game.  Understanding how programs are arranged not only gives you an idea of how much work would go into hacking the game a specific way, but also may give you ideas on how information might be stored in the ROM.



Anything the target system can do, you can have your hack do.  Nothing is so much "impossible" unless the original system couldn't do it.  Some things may take a ridiculous amount of work, though, making them impractical.


You can get a disassembly, which isn't quite the same as the source (the source would have comments, variable names, etc -- whereas the disassembly would just have raw addresses and no comments)

But yes -- you can edit that assembly to add in your own code to make the game do pretty much whatever you want.


Not through ROM hacking.

Keep in mind that emulation mimics a target system (in this case, the NES).  So having a game connect to a server isn't going to happen because the NES didn't allow games to connect to the internet.

But can you put in 2P coop?  Sure.  Though both players have to share the same screen, so this is probably one of those impractical ideas.



I'm at a loss to recommend introductory tutorials and stuff.  It's been such a long time since I've been a newb that I don't really know what is useful to newcomers anymore.  If you have experience with a programming language already, you may want to just dive right into assembly (compared to something like C/C++, 6502 assembly is incredibly simple).  Perhaps pick up Doppleganger's SMB disassembly as an example of how games are arranged and some 6502 docs


 :thumbsup:

It differs.  x86 from what I understand is closer to z80 (like what the GB uses).

The NES uses 6502 which is a bit different.  6502 only has 3 work registers, so you end up using RAM for work space more often than you might have to on other platforms.

Some simple simple 6502 and the equivilent C/C++:

C/C++:

equivilent 6502 (commented):

Actually I can think of how this could be possible two ways:

1) Like Disch said, make a multiplayer hack and play it over netplay (though this would be a small number of players).

2) With a heavily modified game and a customized emulator and a server you could pull it off. Have the emulator get a certain memory bank or something and share that between a server.

Umm, I *really* wouldn't recommend my SMB disassembly to beginners of either coding or hacking.  ;-D