Just finished the campaign today. According to Steam, I spent 47 hours and completed all the side missions that I discovered. I deliberately went for a non-combative play-through because I found the idea that I could complete an entire RPG without killing highly refreshing. Disclosure: I'm a Kickstarter of backer of this game.
The game is, imo, very disconnected. There are so many characters from so many different worlds, timelines, alternative dimensions, etc that not only the main narrative but the side quests as well get lost in the "noise". That isn't to say that the main story and individual side quests/characters are poorly written - they're not, but they just get lost in an world that is so obtuse, overwhelming, confusing, complex and impenetrable that they lose a lot of the impact they otherwise might have had.
A further issue is perhaps the amount of reading you need to do - the game has almost no voice acting. Everything revolves around reading copious screeds of text that you can react to with a lot of perceived personal choices (I say "perceived" because I'm not at all sure that it makes any real difference what course of action you choose). There are almost no real truly "reactive" tangible/concrete decisions offered to resolve most encounters - regardless of what you pick (or how you go about something), most of them lead to same basic outcome (similar to Telltale's adventure games). I could be wrong, but I have a feeling a great deal of this game is effectively smoke and mirrors - i.e. a factually mostly shallow experience that is hidden by obtuse/complicated lore and irrelevant dialogue "choices" to make you feel it's more "reactive" than it actually is.
In Fallout 4 your options might be to 1) "Push the Button" and 2) "Leave the Button Alone". In Tides of Numenera it's 1) "[Anamnesis]: Try and remember when you saw the button before"; 2) "[Lore, Machinery] Try to establish what the button does"; 3) "[Persuasion]: Attempt to convince the guard to push the button"; 4) "[Smashing]: Destroy the console"; 5) "[Lore, Mystical] Use your knowledge of The Button God to override the console"; 6) "Use your Amulet of Undoing to deactivate the console"; 7) [Tidal Surge] Destroy the console using your Tidal force"; 8) "[Quick Fingers] Push the button when no-one is looking"; 9) "Leave the button alone". The point being that it's STILL a simple binary choice.
For the record, I'm a big fan of these type of games, but this is not anywhere near the experience of, as a relevant comparison, NWN2: Mask of the Betrayer (which I feel is a far better spiritual successor to the original Planescape: Torment than Tides of Numenera).
5/10, which I consider a take it or leave it score. i.e. you'll neither gain or lose anything playing it.