I have no background in law, so I might be talking out of my ass here, but if my understanding is correct, a court ruling a few years ago clarified public domain in regards to animation so that anyone is free to distribute actual materials from cartoons that have fallen into the public domain, but are not allowed to create wholly new material or publicize their products through use of the still-protected trademark.
In the court case
, a clothing company was using images of Betty Boop off of a poster that had never been copyrighted. Numerous other cartoons, especially those from Fleischer, have lapsed into the public domain. Numerous companies have pumped out copies of these cartoons in varying quality formats, unrestricted by copyright, and selling them under names like, "Classic Cartoons," instead of "Betty Boop."
If I'm interpreting the law correctly, this means they're available as assets to be used elsewhere as well (as in the precedent-setting case of the clothing manufacturer). My line of thinking is that something like Popeye Meets Ali Baba
, which is public domain in the U.S., might provide enough useful backgrounds to furnish a short desert-based adventure game. If you're lazy, you might even find someone who's done the hard work of extracting some of the backgrounds for you
I'm not sure how far this can be stretched (for instance, would trace-overs of walk cycles from PD cartoons be allowed?), and you probably don't want to make an actual Popeye game, but I thought I'd throw this out as food for thought. Perhaps someone with a better grasp of the legal system could clarify things.