There is an old game, circa 199Xs, which I'd like to do a remake. It's an old project of mine and I finally have the time to start it.
The game is definitely abandonware so I don't see the problem in re-using the game's art for the remake.
So far I have reverse engineered the sound format and successfully extracted the game's sound. However, the file formats for the graphics is way more tricky... being a 199xs game, there is a whole lot of indices across files and different color palettes.
The game's code (binary) doesn't help much either... its code over code, a real mess to reverse. Instead of this laborious approach I'm moving towards a smart one.
The game uses DirectX, which I'm not familiar with, I've only used OpenGL all my life. Still, I'm fairly certain it's possible to intercept (hook) the DirectX calls the game uses and extract the graphics art there.
Not being familiar with DX, I have no idea which APIs I should hook, what I should look at or even if there are existent tools that will perform this task.
The concept of "abandonware" doesn't actually have any legal basis, and unless the title has been explicitly released under some free licence or placed in the public domain it's incredibly unlikely that the property doesn't belong to anyone. Even if the original developer and publisher are both out of business any intellectual properties they owned would have been divided up and passed on to other legal entities. You're still running the risk of legal problems.
That being said, if your remake is not-for-profit it's normally ok if you write your software so that it actually loads and uses the data-files from the original product, so that users would need to already own a copy of the original to play. A number of other remake projects have worked this way. I believe you would still not be 100% legally safe, but it's significantly safer than actually ripping and distributing the assets.
Which version of DirectX does the game use? Is there any documentation for the format in question online?