Killer Sudoku Play
Classic sudoku with a math twist: cells are grouped into "cages" that must add up to a target without repeating numbers. Built on top of Sudoku Play, it reached the App Store in about 16 days.
6,000
Puzzles
5,900
Adventure levels
6
Difficulties
4
Game modes
1v1
Duels with friends
~16 days
From zero to App Store
What players get
The game
A board with cages
9x9 grid with cages in 6 colors, the target sum on each one, and the selected cage highlighted.
Tells you when you go over
Checks row, column, 3x3 box AND cage as you play: flags sums that go over and repeated numbers in a cage.
Possible combinations
Shows which number combinations can go in each cage, based on its size, its sum and the numbers already placed.
Notes and hints
Per-cell candidates that can clear themselves automatically, and hints with a daily limit or in exchange for an ad.
Game modes
Classic
Free play across 6 difficulty levels, with a timer, a mistake count and a score based on difficulty, time and accuracy.
Adventure mode
5,900 levels across 6 worlds, with hearts, stars for how well you play and gates to unlock.
Daily challenge
A puzzle a day with coin and XP rewards that keeps your streak going.
1v1 duels
Challenge friends with coin bets on the same puzzle: fastest time with the fewest mistakes wins.
Friends & progress
Friends
Unique codes, username search, friend requests and a friends leaderboard.
Shared level
Your XP and player level are the same as in Sudoku Play.
Its own economy
Killer has its own coins, streaks and shields, kept apart from Sudoku Play.
Weekly challenges
Changing goals with coin and XP rewards.
How it pays for itself
Optional ads
Ads between games, plus optional ads to earn coins, hints or extra lives.
Premium subscription
No ads, plus premium perks.
Problems we solved
Cages you can read at a glance
The problem: Dashed borders, 6 colors and sums on top of a 9x9 grid with its 3x3 boxes: it could easily look cluttered.
How we solved it: Soft alternating colors, borders shaped to each cage and the box lines drawn on top.
→ A clear board that responds fast.
A new game without starting from scratch
The problem: Killer needed almost everything Sudoku Play had, but with different rules.
How we solved it: What already existed was adapted without touching the original game.
→ Around 80% was reused, and Sudoku Play stayed untouched.
6,000 puzzles with a single solution
The problem: Building Killer puzzles that have exactly one solution takes a lot of work.
How we solved it: Every puzzle is built on a verified solution and sorted by difficulty.
→ 6,000 puzzles across 6 levels, included in the app.
The game closed when you opened it
The problem: If the board took a moment to load, the app closed when you went in to play.
How we solved it: It now shows a loading indicator until the board is ready.
→ No more crash, and a smooth way in.
What it proves if you want your own app
A new product in weeks
Starting from Sudoku Play, Killer went from zero to the App Store in about 16 days, with its own store listing, its own brand and its own revenue.
Same account, separate games
Players keep the same account and level; each game's coins and games never mix.
Works offline
6,000 puzzles stored on the phone: the whole game plays without signal.
Rewards nobody can fake
Every solution and score is checked off the phone; bots and cheaters are quietly set aside.
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Highlights
From zero to the App Store in about 16 days: planning, development, puzzles, testing and publishing
Around 80% reused from Sudoku Play: a new product in a fraction of the time
6,000 puzzles across 6 difficulty levels
Ready for real use: offline play and protection against cheating
One account for three games: Sudoku Play, Color Sudoku Play and Killer share their players
Additional Information
Languages
Spanish + English
Modes
Classic, Adventure, Daily, Duels
Based on
Sudoku Play
Development
~16 days from zero to App Store
A family of games
Same player account as Sudoku Play and Color Sudoku Play: shared XP and level, with each game keeping its own coins.