It's truly a wonderful game and I feel very happy having bought and played it. Yes, as practically everyone else has mentioned, it is short (just finished playing it and it clocked at around four and a half hours), but it never feels rushed - in fact, the pacing and the acts are very well done. I have to disagree with one negative commenter that the third act does not feel like the first two, to me it matched perfectly and the throwbacks were all in good fun. If anything, if the game ever gets the extended/director's cut treatment, I hope they add a chapter between acts 2 and 3 where the some of the actions described in the end take place. Hit me up, SickChicken, I would love to write that!
Most of the reviews here discuss the controls or the puzzles, which are all OK/serviceable - however, there are parts of the protagonist's backstory that are *dark* and not telegraphed in any way in most reviews/trailers. Even the GOG page only says that Kathy has a "troubled past" but there are things about playing her that will offend some people immediately (I feel). These things are not only mentioned in passing, they are important plot elements and are visualized throughout the whole game up to the very end. If you have played "I Have No Mouth And I Must Scream", it's similar to the "yellow episode", but worse, especially since the overall tone of the game never quite matches these individual elements. So just putting this out here: content warnings: mental illness, abortion.
I really enjoy the gameplay and the sound design, HOWEVER: the graphics performance is really sketchy even on modern hardware. You may get really low FPS, making this borderline unplayable at times, and it doesn't help that the in-game graphics options are extremely limited. This is not a GOG-exclusive issue, you can see mentions of this problem over at Steam's forums as well. Unfortunately, it doesn't seem that it will be resolved by the developers, so it all depends on your hardware. YMMV but I figured you should be warned - I wasn't, and this was my first refund here.
The version available at GOG.com is 1.0.3, which suffers from a bug that will completely prevent you from starting it up if you are running Linux with an Intel HD graphics card. This bug has been resolved in version 1.0.4, as reported by users over at Steam (which is supposedly at version 1.0.6 already). The downloadable version here has not been updated in at least 24 hours, and my weekend of fun playing this game has been a weekend of walking the dogs. Can't say I'm very happy.