Mystery Box

What is this game?

Mystery Box is a deduction game on a three-by-three grid of nine boxes. One box holds the level's reward, some hold traps, and the rest are empty. The Intelligence Brief lists clues about the reward's position, and your job is to read them together and open the one box they all point at.

It is not a guessing game. After generating a level the engine runs its own solver: it filters all nine boxes through every clue, and it only deals the level if exactly one box survives and that box is the reward. A level that could have two answers is rejected and regenerated, so every deal is provably solvable from the clues alone.

Levels are dealt from a fixed progression rather than at random difficulty. The trap count is 2 + floor(level / 3), adjusted by the difficulty setting and then clamped between 2 and 7 so there is always at least one safe box and one reward. The clue count rises with level: one clue at level 1, two from level 2, three from level 4, four from level 7 and five from level 10.

How to play

1. Choose a mode and difficultyClassic gives you three lives and the timer you selected. Time Attack rewards fast solves. No Lives is the hardcore variant with a single life, so one trap ends the run. Endless keeps dealing levels. Difficulty is Easy, Normal, Hard or Nightmare, and it shifts the trap count by -1, 0, +1 or +2 within the 2-7 clamp.
2. Read the whole Intelligence Brief firstClues come in categories - position, row and column, adjacency, parity and arithmetic - and they are only useful together. A single clue rarely isolates a box; the level was validated on the intersection of all of them.
3. Eliminate before you openWork out which boxes every clue permits. There is exactly one box that satisfies all of them, so if two candidates remain you have missed the constraint that separates them.
4. Open the boxClick or tap a box, or press its number from 1 to 9, or move with the arrow keys and confirm with Enter or Space. The grid is numbered left to right, top row first: 1-2-3, 4-5-6, 7-8-9.
5. Use a hint only when it is worth 25 pointsPress H or the Tactical Hint button. Two hints are available per round and each costs 25 points from that round's score.

Controls

1 - 9

Open that box directly; the grid numbers left to right, top row first

Arrow keys

Move the selection around the three-by-three grid

Enter / Space

Open the selected box

H

Request a tactical hint - two per round, 25 points each

Esc / P

Pause and resume the round

Scoring and results

The round score, term by term

Score is 100 base + level bonus + speed bonus + life bonus + streak bonus - hint penalty, floored at 20. The level bonus is 35 per level above the first. The speed bonus is 100 under 5 seconds, 75 under 10, 50 under 20, 25 under 30 and nothing at or beyond 30. The life bonus is 25 per life still held, the streak bonus is 20 per streak level beyond the first, and each hint used costs 25.

Lives and the streak

Classic starts with three lives; No Lives mode starts with one. Opening a trap costs a life and resets your streak to zero, and the trap box stays revealed so the information is not wasted. When lives reach zero the run ends and the true reward box is revealed.

What the two hints actually tell you

The first hint is a Tactical Scan: it names an unrevealed trap box and marks it disabled on the grid. If no unrevealed trap is left it becomes a Radar Ping naming the reward's row instead. The second hint is a Deep Sensor and names the reward's column. Both are true statements about this level, never a bluff.

The timer

The timer is your setting - 15, 30, 45 or 60 seconds, or off entirely. It tightens at high levels: five seconds are removed from level 5 with a floor of 15 seconds, and five more from level 9 with a floor of 10 seconds. Choosing no timer removes the pressure and the speed bonus opportunity along with it.

Rewards, traps and career records

Eight reward types cycle by level - Golden Chest, Cosmic Star, Prism Diamond, Ancient Relic, Cyber Matrix, Dragon Pearl, Quantum Core and Sacred Chalice - and six trap types are drawn from Plasma Shock, Toxic Cloud, Cryo Spike, Infernal Blaze, Void Rift and Laser Grid. Best score, best streak and round history (the last twenty rounds) are stored locally under RTK_MYSTERY_BOX_DATA.

What this game tests

• Whether you can combine several constraints instead of acting on the strongest one
• How your deduction holds up under a countdown rather than at leisure
• Whether you spot that two candidate boxes means you have missed a clue, not that the level is ambiguous
• How you trade a 25-point hint against the risk of losing a life and a streak
• Whether you keep deducing after a trap, using the revealed box as new information

Limits worth knowing

A browser can only report what the platform gives it. These are the honest boundaries of this page, so a result is never read as more than it is.

• There is no real money and no purchase of any kind. The rewards are icons and points; the page's own FAQ answers “Does the game use real money?” with no, and there is no payment path, wallet or account anywhere in the game.
• The randomness is unpredictable but not a lottery. Box placement uses crypto.getRandomValues where the browser provides it and falls back to Math.random otherwise, and the result is then filtered through the solver - so the layout is random, but the puzzle it produces always has exactly one provable answer.
• Two hints per round is the hard limit. Asking for a third returns “Hint limit reached for this round” rather than charging you again, and the two hints are position information only - neither one opens a box for you.
• Trap counts cannot grow without bound. Nightmare adds two traps but the final clamp keeps the count between 2 and 7, which the engine notes is there to preserve at least one safe box and one reward on a nine-box grid.
• Scores are local and per browser. Best score, best streak and the last twenty rounds are written to RTK_MYSTERY_BOX_DATA in localStorage; there is no leaderboard, nothing is uploaded, and clearing site data clears your history.

Tips for a higher score

• Do the elimination on paper or in your head before touching the grid. The level is guaranteed to have a single answer, so a confident open beats a hopeful one - and an unopened box costs nothing.
• Save your hints for level 7 and above. From level 7 the deal carries four or five clues, which is where a column ping actually saves you a life; on early levels one clue plus the grid is usually enough.
• Protect the streak when you are down to one life. The streak bonus is 20 points per level of streak, so spending 25 points on a hint to keep a four-deep streak alive is close to break-even and much better than losing it.

Troubleshooting

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