Playdead, developer of the acclaimed 2010 indie game Limbo, is finally back with its second game six years later. Inside, like the studio's freshman effort, is again a monochromatic, tense, haunting, side-scrolling puzzle game, but with six years of effort under its belt, Playdead now delivers a masterclass in its form.

The story of Inside, released today on Xbox One and July 7 on Steam, concerns a boy who's risking life and limb to break into some kind of facility where (you find out rather quickly) some kind of experiments are being conducted on humans. You won't get a whole lot more insight into the plot than that—this is a total pantomime, and there's no writing save for a few dilapidated letters and numbers on formerly legible signs.

You'll be using your imagination to fill in the rest—the darkest parts of it. From the off, Inside sets a beautifully horror-tinged mood as you avoid the headlights of oncoming trucks, or just barely dodge the snarling jaws of an attack dog. Within a minute, you feel like you're really being chased.

Playdead

As a "puzzle platform" game, Inside is 49 percent dexterity and 51 percent problem solving. It's more about figuring out where to push a box to give yourself the perfect jumping-off point, and less about having the reflexes to actually perform the maneuver—although that does matter, too.

It gets more complicated from there, but not too complicated. Inside's greatest strength is its ability to hold back: There's just enough of each type of puzzle to keep you on your toes, but never so much that they wear out their welcome or become overly complicated. Most of Inside's puzzles use just a piece or two of scenery; there's a beauty to its minimalism. The puzzles never feel like Rube Goldberg machines, just artful implementation of a few basic building blocks.

This does result in a game that's fairly easy to complete in a few brief hours for anyone versed in the genre (and maybe even newbies). But it's a tight four hours; you're always doing something interesting and things are varied enough to maintain a nice state of flow.

Inside, like Limbo, can be fairly disturbing, but since it shares the zoomed-out, low-resolution viewpoints of its predecessor, much of that imagery will take place in your mind. Limbo had an Edward Scissorhands cartoonishness at its core, but Inside's more realistic style creates something more and more unsettling.

Don't expect much in the way of answers. Something's inside, but it may leave you with more questions. Why try so hard to break in to a place like this? Whether you figure it out or not, I bet if you try it, you won't be able to stop pressing forward.