Some changes made to the series from the Visual Novel
I finished reading the Visual Novel back in January, and I am 3 episodes away from finishing the anime (not including the OVA which was not covered in the VN anyway)
Obviously adapting the entire VN would have required quite a few more episodes and paths that ended before the true ending, but I was hoping some of the content from other endings would make it into the anime, because for me, they gave more meaning to events in the VN.
Spoilers for anime and Visual Novel below
I think the biggest change was Mr. Braun shooting Moeka. This actually really changed his character from the novel. In the novel, he did point his gun at Moeka, but only shot himself. It was heavily implied that he started to care for Moeka and stopped corresponding with her in order to save her from the Rounders. In the anime, it just seemed like he didn't give a crap about her and killed her. I haven't gotten to the end yet, but in the Novel, the fact that he cared for her comes back in the true ending when he gives her a job. In the Novel, it was Nae who time lept back into herself as a child to kill Moeka. That was kind of an odd part of the VN, which IMO didn't need to be in the anime, but I don't think they should have had Braun kill her.
Another big change was not having Faris trick Okabe into helping her win the Rai Net tournament. I guess that wasn't really important, and the more important stuff actually happened in the Faris ending. I don't anime did a good enough job showing that Faris was falling in love with Okabe though.
I'm sure there are few other discrepancies I am forgetting at the moment.
I was hoping they would insert the time loop part of the Suzuha ending though. That could have been done while still preserving the true ending path. That sequence really made me feel much more attached to Suzuha.
I'm looking forward to reading the Steins;Gate 0 VN and watching the Anime this spring
I just finished the main series (not the OVA) last night.
Another difference between the VN and the show, is that I believe only Faris mentioned remembering anything from alternate worldlines in the VN. In the show it seemed everyone was talking about remembering. IMO that fact really took a lot of weight away from the reveal at the very end that Kurisu remembered Okabe. To me, that was one of the most emotional parts of the VN, and it wasn't handled as well in the TV show.