The best way Berserk anime is described is as a trailer for the manga. It covers the entire flashback part in the manga. Only the first and post-credits part of the last episode are in the present time of the manga.
Basically, the manga has a larger section before the flashback that has present Gutts and characters that are in the present time story, like Puck. They also remove some characters who show up in the flashback for a tiny bit but have more importance in future chapters, like The Skull Knight.
The last scene of the anime is sets up the first episode. The manga is more of that, with Gutts killing demons with his Dragon Slayer.