I only see the full install code. Does this upgrade require a full install?

Depends on how deep they go. Changing some news text and throwing a frame around the existing animation is probably more reasonable. Maybe a snow filter over the graphics if it didn't look terrible.

Throw that in with a custom attract for a few major holidays (quick animation and light board flash) and it wouldn't be a terrible amount of work.

All of that said I am not sure that is work you are getting paid for. I'm curious if anyone thinks holiday themed attracts would draw a few more quarters at the bar-cade.

I think a much cooler use of time would be to create a basic framework for not only a custom attract image but a custom animation/light show you can upload. That is something that could be pushed to all of their machines (assuming a roughly similar software framework) and would effectively crowd source a huge list of animations and images. It could even be a precursor to a framework for custom modes. Smart money is on a pin-ball app store rolling out for these more general purpose platforms (PCs with USB light boards). There could be free to download modules as well some market for custom work. The question is if JJP or Stern do it first. JJP has a better platform for it.

I'm sure the real trouble is in the legalities around someone adding a mode to a licensed IP (even if they couldn't use any IP specifically). I could imagine some additional legal challenges given these go into commercial environments vs. HUO.