The release of the anime Steins;Gate 0 and also the Steam Summer Sale has finally spurred me to buy and play Steins;Gate 0, and what a deep and pleasant surprise it was. Usually, a sequel / spin-off game for a deeply thought-out game like Steins;Gate would be poorly done, but Steins:Gate 0 is certainly an exception to that rule.
I'll try to keep this review as spoiler-free as possible.
Steins;Gate 0 takes place near the end of the true Ending of Steins;Gate (or episode 23 for you anime-watching folks). Specifically, in-between the time when (spoiler alert!) Okabe fails to save Kurisu the first time and the second time. Basically, Steins;Gate 0 explores the very first iteration of the True Ending of Steins;Gate 0, where Okabe never received a Video D-Mail from his future in the year 2025, and all the pains he has to go through to finally open the path to Steins;Gate.
It's worth mentioning that Steins;Gate 0 is darker compared to Steins;Gate with Okabe having to cope with PTSD all throughout the game due to the experiences and choices he made in Steins;Gate. And, you're going to see the start of World War 3. And also, blood. Lots of it.
In terms of the story-telling, the main difference between Steins;Gate and Steins;Gate 0 would be how "branchy" Steins;Gate 0 is. Steins;Gate, for all it's story, was pretty linear. You simply progress through the story and at a certain point of time, you make your choice (with your phone) and the story goes towards the ending of that certain path or heroine.
Steins;Gate 0 is very "branchy". It's not really clear when the branch happens during your first time playing, well at least it wasn't to me. And compared to the original, Steins;Gate 0 doesn't explicitly explain everything that happened to the readers. The readers have to piece themselves from everything that happened in each timeline to finally understand what really happened in each timeline. And really, there are lots of headscratchers and red-herrings that they throw towards you to throw you off your tracks. And it doesn't matter if I've told you there are red herrings, because the misdirection is that good. There are plenty of Chekov's Boomerang across the timelines. Yep, you're going to get your mind blown, just like the first game. Though you'll need to work your brain to really understand what happened throughout the game and (spoiler alert!) when nearly all of the timeline changes was initiated without Okabe being aware of who did it.
In terms of emotional, I still feel Steins;Gate have the Zero beat, simply because of the mood whiplash that Steins;Gate did. But Zero IS still pretty depressing. It's funny at times, but it can get you close to tears too.
So, if you have already read Steins;Gate, then you definitely would not want to miss Steins;Gate 0. It's good. Do it. And if you're a fan of Visual Novels in general but haven't read Steins;Gate yet: get Steins;Gate first. Then continue with Steins;Gate 0. Steins;Gate 0 is pretty much a direct sequel (or technically, inter-quel) so you will NOT understand what's happening in 0 and why they are important. So get on and have your mind blown with Steins;Gate 0!