Okay... But Nintendo doesn't even make the game anymore do they? Isn't their copyright void?
Just a little FYI on intellectual property rights (I used to be in the business, so I know the basics pretty well) in the US--be aware that if you are not living in the US, the rules may be stricter, but these are still good guidelines to be aware of as the basic principles tend to be the same throughout developed nations and most developing nations that are invested in protecting intellectual property (IP):
First off, IP rights are not contingent upon something being actively sold/marketed/recreated. Once something has been created, that's it, the copyright exists
even if it has not been registered. Obviously most people go to the effort to register their IP so as to protect their assets and give them something to hold up in court if they end up in litigation regarding a copyright issue. The entire Zelda series is both copyrighted and registered as a trademark (yes, those are two separate things but there is some overlap in a large franchise such as this); the vast majority of fan works are technically in violation of one or both of these. However, because the fan base is an essential part of the success of a video game franchise, it is very rare for a company as large as Nintendo to actively pursue anyone creating fan works on the basis of copyright infringement, especially as most creators are not making money off of them.
In your specific instance, it is very important for you to know that the game is copyrighted for at least 75 years from the death of its creator. This is the loose, general rule of thumb used for IP in the United States, Canada, and most European countries. This means that LoZ is absolutely still covered under copyright; it does not matter that the game is no longer being manufactured. You should also be aware that completely rebuilding a video game could, even into a text-based format, be viewed as a more significant copyright violation by Nintendo should it ever end up getting widespread attention, especially if you were to make any money from it.
That being said, as Hachi pointed out, very rarely will a company as big as Nintendo go after an individual for a small scale violation. The important things to keep in mind if you want to avoid prosecution would be not to make any money off of it, and to watch how widely available it becomes. Even if it came to Nintendo's attention and they decided to take action, the first thing they would do is send a cease and desist order, telling you to take it down. Complying with the order would prevent any further legal action, although in an extreme case they could require you to destroy the content as well. This is a VERY unlikely scenario, but you should be aware of the potential outcomes involved in this project.
Hope this helps! Feel free to message me if you have other IP questions.