If you've been paying attention, you already know that the GOG Summer Sale is in full swing, with big bundles, fast-flying flash deals and other such digital gaming goodness. New now, and for the next 24 hours, you can snag the first-person puzzle game Magrunner: Dark Pulse for even better than cheap. I'm talkin' 'bout free .

It's a vaguely Portal -esque puzzle game in which a mega-corporation of the future embarks upon a cutting-edge research program and accidentally unleashes the Great Old Ones of the Cthulhu mythos. Seriously, that's it—it's a straight-up sci-fi physics puzzler corrupted by a Lovecraftian invasion, and it's actually pretty good, although Marsh wasn't quite as enthusiastic about it as I am in his review .

But it's free, and it's DRM-free, so there is literally no reason not to grab it. The GOG Summer Sale is escalating in other ways, too, with 30 bundles going on the block for as much as 90 percent off over the same 24-hour period and 30 new flash sales every hour. The Magrunner: Dark Pulse giveaway is on now and runs until 12:59 pm GMT on June 19.