Ah, the more I read about this the more I feel that this is a worse case than Montague's Mount - at least the latter still has its actual and carrying developer behind it.
Well, that's hard to call. One of the awesomest adventure games series in the catalog--Tex Murphy--ended on a cliffhanger that stood for 15 years before there was any word of it being resolved. We sold Overseer with a clear conscience--because the game was good--and as long as the product page properly describes Dark Matter, I don't see where it's a problem if this game ends on a cliffhanger, too.
That's quite an unfair and unconvincing comparison.
Based on the info around the Interent, the IP is in the hands of a company with a very limited portfolio that let the developing team go a few months ago after a failed Kickstarter campaign. The publisher made it crystal-clear that there won't be any more Dark Matter unless they see some money coming in - nobody knows how much is expected.
How likely is it that it'll sell well enough for Iceberg Interactive and InterWave Studios to warrant the continuation? Feedback all over the Internet is negative - on GOG, the game has currently five reviews, three of which say "don't buy, it's unfinished" providing links to support it and listed as the most helpful ones. The response to the backlash has been nth but typical PR talk, which indicates that the entities still related to this IP are not passionate enough about it and its continuation.
I fear there's a bad trend forming that can (will?) potentially hurt GOG. Is it possible that the contracts signed contain clauses that prevent GOG from taking the game(s) down? Or could it be that GOG has handed out the royalties in advance and needs to recoup (at least some of) them? Maybe some combination? I'm just wondering because TET's posts are very carefully worded with PR vocabulary.
Given the two similar incidents within a timeframe of ten days, maybe it's worth (and time?) to reassess the stages and steps of signing new indies.