Scrabble is a good case study for what is allowed, because there are(were) many clones of it, and Hasbro defends it litigiously.
The name of the game or logo, or anything close enough that someone might confuse them, is protected by the trademark
The rulebook wording is copyrighted. So is the artwork on the board/box
Some of the game design can be covered ...
I'm not a legal expert so obviously don't just take my word on it. If you really are worried, it's best to consult a lawyer.
However, from my knowledge, you can not claim any big idea, method, system, etc. For example, I can create a battle royal game and not have PUBG, Fortnite, etc copyright me as that is a game genre. I can also create a power up system, ...
Version control software designed for large binary files would solve this problem.
For example, git lfs provides efficient versioned storage for any type of file with infinite history (provided infinite storage space). It supports commit signing to prevent resource corruption.
Perforce is another example common the game dev industry (source).
The key factor ...
Be unique and present your ideas in a way that no one else can, use your own trademark and and make it stand out from everyone else, create and come up with ideas of what you went your assets to be and make sure, these are your assets and no one elses as this could lead to copyright claims and issues a game developer would not want.
Not legally, no, you cannot use it.
"Abandonware" is not a legal concept, and the original copyright ownership still stands, even if the original product is no longer being sold. Likewise it doesn't matter if you're offering your's for free, you would still be using material that is legally owned by someone else.
Finally, and as always, if you want ...