Early Access is a gamble. Sometimes it works out, sometimes it's... well, Godus (opens in new tab). As such, it's nice to see developers of Interstellar Marines giving potential buyers an idea of what they're potentially buying. For the next week, you can play the game for free through Steam.
For the next five days (and nine hours), anyone can install the game and play it for free. After that, it's whisked away from your library, but a 66% off sale makes it a fair bit cheaper if you do decide to commit.
As for the game itself, it's a tactical FPS inspired by Half-Life, System Shock 2 and Rainbow Six 3: Raven Shield. Expect plenty of sci-fi trappings, a smattering of stealth, and some co-ordinated co-op.
It sounds interesting enough to be worth a look, which you can do by going here (opens in new tab).
As for how Interstellar Marines is progressing, here's a recent update video explaining the latest additions for the game.