UPDATE #2: Dark Matter has been removed from sale on Steam. A notice reads: "Currently there is a known issue at the end of the game. The developer is aware of the issue and they are working on a patch as a solution."
So, Dark Matter's a new indie Metroidvania-styled game. Wait, come back! Developer InterWave's promising to distinguish itself from the thickening crowd of similar games by putting a slant on the adventure side of exploration, as well as throwing in a handful of novel mechanics - and with the well-received Nuclear Dawn under their belts, it's a promise they should come good on.