BLUFF

"Train your brain to smell a lie."

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Inspiration

I've always believed the best way to learn something is to be tricked by it first.

Think about it — you forget a fact you read in a textbook in a week. But a fact that fooled you? You remember that for years. The embarrassment, the "wait, seriously?!" moment, the explanation that reframes everything you thought you knew — that sticks.

That's what BLUFF was born from. I wanted to build a game that doesn't feel like studying but makes you genuinely smarter every time you play. The kind of game you open when you're bored on the bus and suddenly look up to realize you missed your stop.

The other spark was watching how Wordle took over the world — not because it was technically impressive, but because it gave everyone one thing to solve together each day and a way to share it. I wanted that same daily ritual energy, but for facts, lies, and the thrill of catching both.

What it does

BLUFF is a daily brain game where every round you're shown 3 statements — 2 are real, surprising facts. 1 is a beautifully crafted lie that sounds completely believable.

Your job: catch the lie in 45 seconds.

🔗 Play it live: app-blvfcf1drqip.appmedo.com

  • 🧠 AI-powered rounds — every round is generated fresh by AI, pulling from categories like Science, History, Animals, Space, Psychology, Food, Movies and more. No two sessions are ever the same.
  • 📅 Daily Challenge — the same 5 rounds for every player each day, with a shareable result card. Pure Wordle energy.
  • ⚡ Speed bonus — the faster you answer correctly, the more points you earn. Every second on that 45s timer counts.
  • 🔥 Streak system — play every day to build your streak. Miss a day and it resets. Simple, brutal, effective.
  • 📈 5 difficulty levels — from "obvious myths" at Level 1 to "the lie hides inside a sentence that's almost entirely true" at Level 5, with auto-scaling as you improve.
  • 🏆 Brain Rank titles — climb from Rookie Detector all the way to The Lie Whisperer as your XP grows.
  • 📓 Notebook UI — warm, papery, handwritten aesthetic that makes every round feel like a clever quiz on a real notebook page.

"Every fact is real. One of them isn't. Can you tell the difference?"

How we built it

BLUFF was built entirely on MeDo — no traditional coding environment, no separate backend, no external database.

The entire architecture rests on two pillars:

1. The AI/LLM Plugin — the game engine

Every round, MeDo's AI plugin is called with a structured prompt that instructs it to generate 2 true facts and 1 crafted lie about a random category, at the current difficulty level, in a specific JSON format. The AI also writes the explanation shown after each answer. The topics used in the session are passed back into the prompt each round so the AI never repeats itself.

Getting the lies right took real iteration. Early prompts produced lies that were either too obvious or too obscure. The breakthrough was instructing the AI to craft lies that are partially true — where the core fact is real but one subtle detail (a number, a name, a date) is wrong. Level 5 rounds use this technique exclusively.

2. Browser localStorage — the memory

With only the AI/LLM plugin available, the entire persistence layer was engineered using localStorage. Ten specific keys track everything: streaks, XP, total score, accuracy history, seen topics, daily challenge completion, and rank. The daily challenge uses today's date as a seed passed into the AI prompt — ensuring all players get the same puzzle without any server coordination.

The result: one AI plugin + browser storage = a fully functional, stateful game with zero backend.

Challenges we ran into

Getting the AI to lie convincingly was harder than expected. Early prompts produced lies that were either too obvious ("the sky is green") or too obscure to be interesting. The breakthrough was prompting the AI to craft lies that are partially true — where the core fact is real but one detail is subtly wrong. Level 5 rounds use this technique exclusively.

No-repeat logic without a database was a real constraint. The solution was clean: maintain a seen-topics array in localStorage, pass it into every AI call, and let the AI handle avoidance naturally. It works because the AI's knowledge base is vast enough that topic exhaustion is practically impossible.

The daily challenge consistency problem — how do all players get the same puzzle without a server? The answer was using today's date as a fixed seed in the AI prompt. Same seed, consistent output. Zero infrastructure.

Balancing fun vs. frustration — a lie that's too easy feels boring. One that's too hard feels unfair. The 5-level auto-scaling system solved this: BLUFF meets players at their level and pushes them forward without punishing them for being new.

Only one plugin available — no database, no share plugin, no notifications. Every feature had to be engineered around a single AI/LLM plugin and native browser APIs. This constraint pushed creative solutions that made the architecture cleaner, not messier.

Accomplishments that we're proud of

  • Built a fully stateful game with streaks, XP, ranks, and daily challenges using only one plugin and localStorage — no backend at all
  • Engineered an infinite no-repeat fact engine that generates fresh, accurate, genuinely surprising content on demand
  • Created a daily challenge system that gives all players the same puzzle using only a date seed — zero server coordination needed
  • Designed a 5-tier difficulty system where the hardest lies are technically partially true — a genuinely new kind of brain challenge
  • Shipped a complete, playable product live at app-blvfcf1drqip.appmedo.com within the hackathon window
  • The Notebook UI — every interaction feels warm, physical and satisfying in a way that most browser games don't
  • Achieved a game that teaches real facts as a side effect of trying to catch lies — learning disguised as fun

What we learned

  • The best game mechanics are constraints. 45 seconds. 3 options. 1 lie. No more decisions than that. Simplicity is what makes a game replayable, not complexity.
  • AI is most powerful when it's the engine, not a feature. BLUFF doesn't use AI as a chatbot or an assistant — the AI is the game. Every round is born from it.
  • You don't need a database to build a real product. localStorage, used thoughtfully with a clear key schema, handles most persistence needs for a single-player game. Constraints force creativity.
  • The explanation is as important as the answer. When players learn why they were wrong, frustration turns into delight. Every wrong answer in BLUFF ends with a genuine "oh wow" moment.
  • MeDo removes the distance between idea and product. The gap between "I want to build this" and "this exists on a live URL" collapsed to hours. That's the real unlock.

What's next for BLUFF

  • 🌍 Global leaderboard — real-time daily rankings once a backend is connected
  • 👥 Challenge a friend mode — send someone a specific round and see if they catch the lie faster than you
  • 🗂️ Custom category packs — Science BLUFF, History BLUFF, Sports BLUFF as standalone themed editions
  • 🎓 Classroom mode — teachers set the topic, students compete live. BLUFF as an actual learning tool.
  • 🌐 Multi-language support — the AI engine makes this completely natural; same prompt architecture, different language instruction
  • 📱 Native mobile app — the streak mechanic is made for a home screen icon and a daily nudge notification
  • 🏅 Seasonal events — special Halloween lies, World Cup facts, space exploration packs tied to real-world moments
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