Grey Box Testing
▶ Tap to Play Grey Box Testing
Grey Box Testing is a free indie puzzle game by Sam Hogan, the YouTuber and game developer. You play as a tester inside an unfinished “grey box” prototype — the kind of bare, blocky test level developers build before the art arrives. Your job sounds simple: grab cubes, press buttons, and report bugs. But the bugs are not accidents. They are the game.
This is a short game-jam build, so the full run takes about fifteen minutes. Players compare it to Portal and The Stanley Parable, and one fan called it “the coolest buggy game I have ever played.” Years after release, over 1,400 comments sit on its itch.io page, with players still helping each other beat the moving-box levels.
The Twist: Every Bug Is on Purpose
In Grey Box Testing, pausing the game is a weapon. Hit pause and the world freezes — physics stop, doors hang open, moving platforms lock in place — but you keep moving. Walk through a closing door. Cross a gap on frozen platforms. Step to a wall and phase through it while the world is paused, then unpause on the other side.
That is the genius of it. In any other game, clipping through a wall is a glitch. Here the puzzles are designed around it, and you spend the whole run unsure which broken thing is a real accident. One player summed it up: “I genuinely cannot tell if phasing through the wall is intentional or not — 10/10.” Sam Hogan confirmed in a dev video that yes, the “bugs” are the solution.
The game even rewards you for thinking like a QA tester. Pause while holding a cube and it floats in mid-air. Cubes can be carried between rooms. Drop a box on a pressure plate from a ledge and skip whole sections. It all counts.
All Four Levels, Explained
Level 1 — Learn to Pause
The first room teaches the loop: grab the red cube, drop it on the big floor button, and the door opens. The catch: the narrator starts talking, and players who rush ahead throw their cube somewhere useless before the instructions finish. Slow down, listen, keep your cube close.
Level 2 — The Button and the Shortcut
Another cube, another pressure plate — but now you know the pause trick. Stand on the button, pause, walk through the open door, unpause. The “proper” solution and the cheat solution are the same thing here, and that is the point.
Level 3 — The Moving Boxes
This is where players get stuck. One room has a short and a tall moving box; the other has three moving platforms over a gap. For the short-and-tall box room, let a moving box push you against the left wall — you will clip right through it. For the platforms, pause the instant they line up and walk across them like a bridge. Watch for real bugs too: players report sometimes falling through the floor here and restarting the room.
Level 4 — The Narrator Turns
The level players remember most. The tone shifts, the narrator gets stranger, and the final puzzle needs real thought. Without spoiling it: everything you learned about “cheating” applies, and the ending area — literally called “The End” — holds the game’s biggest secret.
The Yellow Cube, the Ending, and the “Boxes” Secret
Beat the game normally and you get an ending. But players found a hidden yellow cube above the ending room. To grab it, noclip upward near the final area and fall into a secret chamber. The classic trick: sacrifice a red cube to phase through the ceiling and claim the yellow one.
Then there is the community’s favorite self-made challenge: carry all four cubes to The End. Players post screenshots of all four red cubes in the final room, some bringing the yellow one too. Speedrunners joined in as well, with records under forty seconds using out-of-bounds clips. The game also flashes your own name on the ending screen, which unsettled more than a few players.
Controls and Pro Tips
The controls are simple: WASD to move, mouse to look, click to grab a cube, pause whenever you want. The web version can feel twitchy — sensitivity runs high and the camera sometimes drifts, so lower it before starting.
A few tips from veterans. Never throw a cube before the narrator finishes talking — you can soft-lock a room. Pause while holding a cube to freeze it in the air; that solves several tricky jumps. And do not be afraid to break the game: walking diagonally through gaps, carrying cubes between rooms, and phasing through doors all work because they are supposed to. If it feels like cheating, it is probably the answer.
Why Horror Fans Keep Coming Back
It starts as a puzzle game and ends somewhere darker. The narrator’s voice, the empty grey rooms, and the feeling that the game is watching you test it give the whole thing a creepy undercurrent. Players who expected a comedy puzzle found themselves unnerved by the final levels, and the hidden yellow cube keeps theorists hunting for lore. Short, free, and unlike anything else on itch.io — a puzzle game where the bugs are the story.
FAQs
What is Grey Box Testing about?
Grey Box Testing is a free indie game by Sam Hogan where you play a game tester inside an unfinished grey-box prototype. The twist is that the world’s bugs — pausing time, clipping through walls, floating objects — are the actual puzzle solutions, and the game slowly turns creepy as the narrator takes over.
Is the game free?
Yes, it is completely free on the developer’s itch.io page. No payment, no account, no ads. It runs in your browser, and a downloadable PC version exists for players who want smoother performance.
How do you beat the moving boxes level?
In the moving boxes room, let a box push you against the left wall and you will phase through it. In the three-platform room, pause the instant the platforms line up and walk across them. Pausing freezes the platforms but not you — that is the intended solution.
How do you get the yellow cube?
Noclip above the ending room by phasing upward near the final area, then fall into the secret chamber to grab the hidden yellow cube. Most players sacrifice a red cube to phase through the ceiling and reach it.
Can you play it on mobile?
There is a browser version, but players report rough controls on mobile — it plays best on PC with a mouse and keyboard. Lower your sensitivity before starting for the smoothest experience.
How long does it take to finish?
Most players finish in about fifteen minutes on a first run. Speedrunners have beaten it in under forty seconds using out-of-bounds clips, and completionists spend longer collecting all four cubes and hunting the hidden yellow one.
Stuck on the moving boxes or found the yellow cube in Grey Box Testing? Drop a comment below and tell us how your run went — or share your own bug trick.
