Hangul Monsters and Math Monsters Are Now Completely Free
We removed every in-app purchase from our two kids' learning apps. After a week with zero sales, we decided that an educational app for young children should simply be open to everyone.
Fadongkwon Soft
Fadongkwon Soft
A solo developer building small apps after work — and writing down what the process actually taught me.
Three things live here. A tarot dictionary covering the meaning of all 78 cards, written from the traditional Rider–Waite imagery with artwork drawn for the apps. Notes on learning apps I built for my own children, and the study material I gathered along the way. And development records — store reviews that rejected me, platform policy differences, and how one person keeps a dozen apps alive.
Shipping Six Mini Games at Once — A Five-Day Retrospective
Sudoku, Nonogram, All Lights Off, Hangul Word Guess, Tap Bird and Number Rush went live on Google Play and Apps in Toss within five days. Why one shared spec, the one-pass registration order, and t...
Number Rush — Tap 1 to 25 in Order as Fast as You Can
A reflex and focus challenge where you tap scattered numbers from 1 to 25 in order against the clock, with millisecond best times and score sharing, now on Google Play and Apps in Toss
Tap Bird — A One-Finger Arcade Flight Through the Gaps
Tap to flap and slip through the gaps in this one-touch arcade game with a free revive per run, best scores, rank badges and score sharing, now on Google Play and Apps in Toss
Hangul Word Guess — A Korean Wordle Played One Jamo at a Time
A daily Korean word puzzle in the Wordle style, where you guess the hidden word across six jamo tiles with color feedback, hints and stats — great for Korean learners. Now on Google Play and Apps i...
All Lights Off — The Classic Toggle Puzzle With Daily Boards
Tap a light and its neighbors flip too. A classic lights-out puzzle with level select, star ratings, daily boards and precise hints, now on Google Play and Apps in Toss
Nonogram — Reveal Hidden Pixel Art With Number Clues
A picture-logic (nonogram, picross) puzzle game where every board is solvable by pure logic, with daily puzzles, hints and auto-save, now on Google Play and Apps in Toss
Sudoku — A Clean Daily Sudoku With Four Difficulties
A daily sudoku game with streaks, four difficulties from Easy to Expert, notes, hints and auto-save, now on Google Play and Apps in Toss
How to Become a Nursing Assistant in Korea — Requirements and Exam
Eligibility for the Korean nursing assistant national exam, the required training hours, the exam subjects and passing marks, and the annual schedule.
The Day We Quit Kumon, Dad Started Building a Math Game
After my eldest quit Kumon math, I built an app to keep the arithmetic practice going — the story of a personal app with my son's photo as its icon becoming Math Monsters.