I initially bought this game at full price due to the positive early reviews (which were mostly based on the first chapter).
Unfortunately, the game is severely broken for many users and the developers have done little to fix these issues since the game's release. These are not only minor bugs or annoyances, but critical game breaking issues.
I usually love these types of adventure games, but in this case, I have been unable to progress beyond the first chapter (disregard the deceptive amount of hours on record; I have left the game running in the background on several occasions while running errands, sleeping or looking for solutions to the problems I've encountered). It is unlikely that I will get a refund as I bought the game long before Steam's refund policies were changed. Instead, I want to warn future potential buyers of the problems they may encounter.
Take a look at the forum posts below:
Bug thread (13 pages so far): https://steamcommunity.com/app/233370/discussions/0/846959998013346908/
Save games disappearing (this is my biggest issue at the moment, as you can see by my posts to the below threads):https://steamcommunity.com/app/233370/discussions/0/594820656460543503/https://steamcommunity.com/app/233370/discussions/0/540734168144496448/https://steamcommunity.com/app/233370/discussions/0/34095131971716840/
Linux/Mac issues (there are too many of these threads to list them all):https://steamcommunity.com/app/233370/discussions/0/540736320066916724/https://steamcommunity.com/app/233370/discussions/0/540732596570915707/https://steamcommunity.com/app/233370/discussions/0/540734792154348290/https://steamcommunity.com/app/233370/discussions/0/540736780877897495/https://steamcommunity.com/app/233370/discussions/0/846959875998907603/https://steamcommunity.com/app/233370/discussions/0/846959876007904035/
More examples can be found on the game's discussion page and I recommend reading through it. These issues have NOT been fixed, despite the game having been out for two years now.
This leaves the game unplayable for many people; whether you are going to be one of these people depends on your luck and on your operating system. Mac and Linux users seem to have the most issues. As the game is listed as being compatible on these operating systems, this is inexcusable.
As for the game itself (or the little I have been able to experience of it), the story is an obvious homage to Agatha Christie's Hercule Poirot. The first chapter starts off slow, but quickly builds up suspense once the titular "Raven" makes an appearance. I have heard that the second and third chapters are a bit of a let down compared to the first chapter's conclusion. The puzzles are alright, but nothing memorable comes to mind. They mainly seem to revolve around using the right object in the right location. I didn't encounter any logic puzzles or truly creative solutions. There is some pixel hunting involved, which I found annoying in the initial train sequence (although it is possible to reveal hot spots in the game by using up "points", this locks certain achievements from being accomplished). The animation and movement in the game is frankly awful, but I was able to ignore it for the most part. It does not really compare well to contemporary medium-high budget games, and as such the standard asking price is a tad steep. I would write more about the game itself, but my save games were erased three times in a row and I have given up on making any progress beyond this chapter.
Basically, if you play on Mac or Linux: DO NOT BUY THIS GAME!
If you play on Windows... buy at your own risk. The first chapter seems decent enough; I can't personally comment on the final two chapters, but many reviews online seem to paint them in a rather mediocre light. Even if you do not encounter the technical issues that apply to Mac or Linux users, the game is still rife with random bugs which can impede your progress. I'd wait for a sale, or hope that the developers finally take notice of these issues and release a patch.