Relax. It's amazing.
Much as Mark Hamill is Luke Skywalker, Henry Cavill is now Geralt of Rivia. If there were ever any doubts or doubters, those are both gone. Cavill is not the only only perfectly cast. In fact, I'm hard-pressed to find any character that wasn't spot on (my only minor complaint was Tris).
One reviewer disliked the editing and effects and I respectfully disagree. Never did I feel like any scene was done an injustice by either. In fact, much of the sword play, in my mind, was stunning, perfectly capturing Geralt's ability to powerfully slice through almost every enemy like cheese. I was pleasantly surprised that the instead of choosing to go over-the-top with CGI, we were treated with minimal effects, receiving only enough to blend into the scene at hand instead of dominating it.
Finally, the story. I will say that the way the timeline and story fits together can be somewhat confusing. That said, the source material is incredibly difficult to weave together into a perfectly coherent timeline at times too. Therefore, I can't hold it against the writers/producers for how they chose to show season one unfolding. I'd challenge even the most dedicated fans to coherently explain the Witcher timeline and insert the main characters without backtracking and making adjustments along the way. To not only tell a huge tale, but also introduce an entire world, it's lore, it's characters, and do it satisfyingly in a single season, as they have done is quite an achievement.
I couldn't be happier with this adaptation on all levels. Truly, this is a magnificent season that does The Witcher justice in every way. It should absolutely not be missed by ANY fan of the books and/or games, and will also serve as great entertainment for fantasy fans as well.