This is a tough one to review. Here's the thing. I think this is a very well done game and I think it would be a ton of fun for the right game group. It just isn't really my thing and I don't know if I can put my finger on just why. In some ways, it's very 90s. A lot of tabletop RPGs from that decade were about the occult, conspiracy theories, and playing supernatural beings. Obviously, Vampire: The Masquerade was the most popular and most famous, but the concept was explored in countless games. Among them, Nephilim stands tall as one of the highest quality. Originally published in France, it was translated and brought to American (and British, I'm assuming) audiences by Chaosium, including the late, great gaming god Greg Stafford. There are mechanical similarities to Call of Cthulhu and other Basic Role-Playing -based games, yet it has a feel all its own.
In the 90s, I was lucky enough to game with a wide variety of people and able to sample a wide variety of games. I did get a chance to play a session or two of Nephilim, but if I'm honest, it left me cold. Reading the game again for the first time in 25 years, it still kinda does. The concepts are cool and they're well handled. They just don't especially interest me.
It's a game I'd happily play if I were in a regular group and someone really wanted to run it. Sign me up. I'll be there. But would I go out of my way to play? Nope. Do I have any interest in running it? Double-nope.
If you read about the game's concepts and it sounds interesting to you, go for it. I think you'll really dig it.