Decoder Terminal vs Codebreaker

A secret cipher of four colored keys is hidden inside the system. You have seven attempts to crack it. DECODER is a code-breaking puzzle — a modern take on the classic Mastermind — wrapped in the aesthetic of a green-on-black decryption terminal. Lock in a guess, hit RUN, and the system reports back: • HIT — right color, right slot • NEAR — right color, wrong slot The hints never tell you WHICH slot is right. Read them, reason it out, and narrow the cipher down before your attempts run out. Crack it in four hits to breach the system. Burn all seven and the cipher stays sealed. NO LUCK. JUST LOGIC. Every cipher is solvable by pure deduction. There are no power-ups, no timers, no ads, no accounts — just you against the code. TWO CLEARANCE LEVELS • EASY · 6 colors — learn the ropes • ADVANCED · 8 colors — for hardened operators Colors can repeat, so don't assume the obvious. BUILT FOR THE CRAFT • A tactile CRT terminal interface — scanlines, glow, and a blinking cursor • Colorblind-friendly: every key carries a letter, never color alone • Honors Reduce Motion • Tracks your stats per clearance level: solve rate, current streak, and best run • Fully offline. No sign-up, no tracking, no nonsense. Read the hints. Breach the system.

Ever wanted a fair game of Codebreaker with your kids, grandkids, or someone far less experienced? Now you can. In casual direct challenges, each player can face a different difficulty. You might solve 6 digits in base 16 while they solve 3 digits in base 10. Same match, same rules, but both players get a real challenge. Nobody has to pretend. Ranked play is the opposite. Both players always face identical settings, so every match is a fair fight. Win and climb the global Elo ladder from Bronze to Diamond. Play against friends, other players, AI, or on your own. Take turns guessing the secret code. Every guess is marked: • X = correct digit in the correct position • O = correct digit in the wrong position Every clue stays on the screen. What you do with the information is the whole game. PLAY OFFLINE • Challenge the AI across five difficulty levels: Easy, Medium, Hard, Master, and Adaptive. • Easy plays like a beginner and can lose track of earlier clues. • Medium and Hard progressively improve their deduction. • Master plays the strongest game the solver can manage. • Adaptive learns from your recent results and adjusts to your level. • Solve a new deduction puzzle every day. • Browse a full archive of 30 past daily puzzles. • Generate unlimited practice puzzles. • AI matches and practice puzzles work with no internet connection. PLAY ONLINE • Ranked matches affect your Elo rating and use identical settings for both players. • Unranked matches let you play with nothing on the line. • Unranked direct challenges let each player set their own difficulty, so players of very different skill levels can still have a competitive game. • Choose optional turn timers: Relaxed, Standard, Speed, Blitz, or no clock at all. • Get push notifications for challenges and tap Rematch as soon as a game ends. • All players share the same global ladder and community. RANKING • Beat stronger players to gain more Elo. • New players begin provisional so the system can quickly place them. • Climb through Bronze, Silver, Gold, Platinum, and Diamond. • Track your place on the global leaderboard and review your full match history. SET YOUR DIFFICULTY • 3 to 7 digits • Bases 5 to 16 A 3-digit base-8 code is a warm-up. A 7-digit base-16 code is a genuine problem. BUILT-IN NOTEPAD Track your reasoning without paper. Mark digits as confirmed or ruled out, and pin them to positions as you narrow down the code. ACHIEVEMENTS Unlock 26 badges across four categories: • Puzzle — daily streaks from a week to a full year • VS AI — AI Crusher for beating Master difficulty • Online — Hat Trick for three wins in a row, plus tier badges at Gold, Platinum, and Diamond • Career — long-haul totals across everything you play RETRO TERMINAL STYLE The whole game is styled like a computer terminal from 1983. FREE TO PLAY Play offline on your own, or sign in with Google, Apple, or email to play online, climb the leaderboard, unlock achievements, and keep your progress across devices. Whether you want a quick puzzle, a fair match with family, or a climb toward Diamond, there is always another code to break.