It really depends on what the remake is like.
Sometimes they take the game and just remake it 1:1 but with updated graphics and maybe some mechanical tweaks.
However, there are also cases where the remake adds new content, and that can be risky. There is usually a large time gap between the original and the remake, and the possible danger here is that the creators have since gotten out of touch with their original work. The result may be extra content that feels disconnected and abruptly different from the rest of the game. Sometimes they pull it off right, but there are also times where the implementation is so messy it feels like a haphazard attempt to pad out gameplay time (which it usually is). At worst it feels like the extra content is not even remotely part of the same game.
If you compare making a game to building a mansion: After the construction has been finished for several years, you can try to nail an extra room to the second floor and it will increase your living space, but there's a definite chance it will make the building look like crap. And if you did an especially poor job, the thing will fall off and kill everyone who is currently in it.