So now that we have some idea of what happens after Minecraft, here’s another question: what happens after Portal? I always think of Gabe Newell at the beginning of the Portal developer commentary track, saying “we think we are just at the beginning of taking advantage of this kind of gameplay.”

What kind of gameplay did he mean, exactly? First person puzzle-solving? Non-violent? Based in weird, unnatural relationships to time and space?

Even if you assume that he meant all of those things at once, and if we throw in absurdist humor and a sense of menace as additional criteria, there are several potential successors in the running. There is of course Portal 2, which played feature film to the original’s short form art house experiment. There is Q.U.B.E., the first Indie Fund game, and Quantum Conundrum, the ambitious but unfocused follow-up from Kim Swift, project lead on the original Portal.

And now, after years of tweaking and polishing, there is Alexander Bruce’s Antichamber—the purest, most tightly designed, most fearlessly, obtusely batshit step out of Portal‘s long shadow that we’ve seen so far.

Here is what makes the obtuseness and batshittery of Antichamber so fearless: unlike Portal 2, Antichanber is not the least bit afraid of the player getting lost, or getting stumped, or having some sort of existential crisis. Antichamber embraces these possible dangers. You’ll get stuck, but the game’s branching, open-ended structure means that you’ll generally be stuck in three to five places at once, which is to say not exactly stuck at all. You’ll find yourself without the necessary tools (intellectual or diegetic) for a given puzzle, but (if that room’s Hallmark card/fortune cookie of a hint proves insufficiently enlightening) the answer is invariably to continue ambling and continue experimenting.

The game’s points of interaction, much like its spartan visuals and impressionistic soundtrack, are at once strictly minimal and psychedelically open-ended. There are puzzles involving blocks, and gun-shaped tools that manipulate those blocks in fascinating, unspecified ways—but especially for the first third of the game, most of the puzzles quite literally involve nothing more than looking at things differently. Turn back down a corridor instead of going forward and something interesting happens. Look up when a sign says Don’t Look Down and something interesting happens. Look closely through a colored window instead of simply walking around it and—well, you get the idea.

On one had, you’re doing about as little as you could reasonably be doing in this kind of game: you’re walking, and you’re looking. But on the other hand, the game is asking you to engage in all manner of non-standard (and as has often been pointed out, non-Euclidean) reasoning. Where Portal was all tutorial and linear escalation, Antichamber is one long final level, a Level 9 of the mind, rich with apparent blind alleys that gradually turn into unexpected intersections. It’s a structure that is bewildering, disorienting, and memorizing in equal measure.

It may be that, when designers truly were “just at the beginning of taking advantage of this kind of gameplay,” there was no choice but to guide players carefully and patiently away from naturalistic or conventional ways of dealing with space, with physics, with games as such. But Antichamber dares to trust that, hey, if you’re playing the game, then you must be willing to suspend your disbelief, your spacial skepticism. You’re here to make sense of things that make no apparent sense. Seriously, by now you know why you’re here, don’t you?

In its brazen forward momentum, as well as in its seemingly impossible ratio of intellectual demands to discrete player actions, Antichamber offers something genuinely new. It’s a considerable step—maybe not forward, exactly; the game will be too opaque for many players, and so it might not seep it into the general bloodstream of indie game design, at least not at first. But it’s a step so confident and so singular that it deserves the attention of the entire Portal-loving world.

And it’s also a game more sensitive to spoilers than any game with a plot, so here’s where I encourage you to play it in emphatic but frustratingly vague terms, and here’s where I scamper off to play the thing some more.