I just looked at the dev's other game Radiant to see if there was any news and there seems to be a Chapter 5 coming in the future.
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Sir Damned:
Thanks for the heads up. It's understandable why they would be worried given the amount of time that's passed. Chapter 5 of Polarity is the end of Part 1 (of 2) of the story, so it's bigger than all 4 previous chapters combined. This is why it's taking a long time. Radiant Chapter 4 will actually be out first, which shouldn't be too much longer.