# Back of the Box

> A film guessing game. Each round shows a spoiler-free plot summary written in
> the style of the blurb on the back of a video rental case, plus four film
> titles. Pick the right one before the clock runs out.

The catalogue holds 1008 films released between 1940 and 2025.
Every blurb was written by hand and deliberately avoids naming the film, its
characters' proper nouns where they give it away, its cast and its poster.

## Playing in a browser

- https://playbackofthebox.com/ — the game
- https://playbackofthebox.com/how-it-works — rules and scoring
- https://playbackofthebox.com/films — the full film list

Answer with keys 1-4, advance with Enter.

## Playing as an agent (no browser)

Two JSON calls. No API key, no accounts, no state held on the server: the token
returned by the first call carries the game.

1. Deal a game:

   POST https://playbackofthebox.com/api/game
   content-type: application/json
   {"difficulty":"classic","format":"ten"}

   difficulty: casual | classic | cinephile  (default classic)
   format:     ten | survival                (default ten)
   rounds:     survival only, 1-100          (default 40)

   The response holds a token and the rounds. Each round has a blurb and four
   options with ids. The correct answer is not in the response.

2. Submit your answers:

   POST https://playbackofthebox.com/api/game/score
   content-type: application/json
   {"token":"<from step 1>","answers":["<option id per round>"],"times":[1234]}

   answers is in round order. null or a missing entry counts as wrong.
   times is optional milliseconds per round; supply it to earn the speed bonus.

   The response reveals the correct answer for each round and the total score.

## Scoring

A correct answer scores 100, plus up to 100 for speed, plus up to 50 for an
obscure film. Consecutive correct answers multiply the round total: x1.25 from
two in a row, x1.5 from four, x2 from six. Best-of-10 pays 250
more for a flawless run. A wrong answer scores nothing and resets the streak.

In survival, scoring stops at your first wrong answer, so a long run is worth
far more than a lucky one.

Self-reported times are only honoured while they add up to no more than the
wall-clock time the game has actually been open. Otherwise the speed bonus is
skipped and the response says so.

## Machine-readable index

https://playbackofthebox.com/api returns the same information as JSON, including the exact scoring
constants and ready-to-run curl examples.