I may be crazy but Willow is a favorite of mine. One of the things that bothers me though is that when you change sword or shield, the items Willow is shown physically carrying never change. I was thinking of starting my first delve into NES hacking/programming with maybe trying this mostly cosmetic hack. There's game logic that equips and dequips the sword and shield, so the real challenge seems to be putting logic in place to change the objects on Willow depending what is selected. The shields look like they could be straight swapped (maybe resized), but the sword may just be a simple color change rather than style. 

So, question to the NES programmers out there... too difficult, not possible, or definitely doable? I'm just starting to look into the inner workings and limitations of the NES chipset. 
 

Definitely doable. If you don't know 6502 at all, modifying the code will be quite difficult though. It can be a little trickier to modify existing programs compared to writing a new ones from scratch. The game uses CHR-RAM, so that is in your favor. And it doesn't max out the memory available to the mapper, so that's helpful too (assuming there's not enough free space in there somewhere). The approach I would guess would be to find the part of the code that loads the graphic data in question, after it executes that then you need to take over, and overwrite some of the tiles with your own tiles depending on the situation.

One issue is that the shield sprites only exist for the face-on orientation.

When Willow swings his sword, or turns to any other facing, the shield is going to look like it switches to something else, unless you do a fairly extensive graphic hack to find a place in memory for the extra shield animations.


The sword palette swap is probably much easier to do.

I was playing last night and was thinking about this as well, I'm thinking of just starting with color swapping shield and sword. That should keep me occupied for months.  

 

I am completely new to 6502, though have learned some assembly in college. Going through bunny man's guides over the next couple of weeks, to get an idea of what I'm in for. 

You'll probably have to get creative with it, since there are enough different shield and sword combinations that you run the risk of having too many colors in use, depending on how you try to mechanize it.

 

Kind of off topic, but monsterx, have you played MR. T Ate My Balls? It's an absolutely hilarious hack of Willow (if not a little crude and childish).

I just came across it recently, but haven't booted it up yet. Definitely going to check it out.