OK, could not wait and went for it.
Late 2013 iMac with 3.1 GHz Intel Core i7
16gb ram
NVIDIA GeForce GT 750M 1024 MB
Runs OK on lower setting, not cranked it up yet to see where it struggles. Long delay on the first load from one area. 1gb 1 gb vram on Cyan web site (min, best is 4) but 2 on the App store.
There has been the odd stall but nothing to make it unplayable, so far..... only just got to the first area.
Try to get to grips with it some more today however the App store fudged itself and a there was an issue in a file that needed deleting to get it to run a second time.
Edit. First load today is taking ages. Four minutes now. Ok. We shall see.... this might be a deal breaker.
Edit 2. If I use auto detect, the settings all go low for mine and it runs very well. No stuttering. Up the settings and even medium start to give issues. Epic is a non starter, obviously.
One load too eight minutes. Not a deal breaker, go do something else for eight minutes.... Tried the language change that some site say may work but not really. Starting to get to the puzzles now and the resolution, all things considered, is good enough on this iMac. Just at the start of the game so no idea if there are more machine intensive area's that will degrade it.