FibDefense: Math Tower Defense

Every hit is a Fibonacci number. Build exact sums, land the final shot at zero, and solve a 34-puzzle Journey across six hand-painted worlds.

Every tower in FibDefense deals Fibonacci damage (1, 2, 3, 5, 8, 13, 21, or 34) and can only fire at a monster if its shot damage is less than or equal to that monster's current HP. No overkill. Ever.

This single rule turns every wave into a living math puzzle. Monsters march with HP values that always have a solution, but finding it requires precise placement, careful timing, and knowing which Fibonacci values chain together to reach the kill. When it clicks, towers drop a monster in a perfect cascade.

PUZZLE MODE 34 hand-built levels, each one a self-contained problem: a fixed gold budget, every wave shown before it comes, and a verified perfect solution waiting to be found. No random drops, no filler — just you, the numbers, and the cleanest line to a five-star solve. Every world lays out its own boards, so each is a full campaign of its own. The first 8 levels are free; one unlock opens all 34 on every world.

SIX WORLDS Fantasy, Sci-Fi, Military, Retro, Pirates, Horror. Each world has its own tower sprites, nine tiers of creeps, a handcrafted environment, and a unique boss that arrives as your ultimate challenge.

FIVE DIFFICULTY LEVELS Relaxed mode lets you spot kill solutions at a glance. Expert mode requires planning multiple towers ahead, with longer Fibonacci chains needed to solve each monster's HP. The difficulty scales in logic, not just stats.

ZECKENDORF MODE: THE ULTIMATE TEST Named for a real theorem, built for perfectionists. In Zeckendorf mode, each Fibonacci value can strike a monster only ONCE, every kill must be composed from different numbers, like building an integer from Fibonacci blocks without repeating a block. Your towers respect the math: no shot ever overshoots, and no tower will fire if it would leave a monster's HP impossible to finish. You get 55 lives (the next Fibonacci number after the 34 tower). You'll need them.

BOSS ENCOUNTERS Survive the waves and a boss appears: massive HP, relentless movement, and a gold reward worth fighting for. In Continuous mode, every boss encounter scales higher. How long can you hold the line?

FREE TO TRY FibDefense is free to play: the Fantasy and Sci-Fi worlds, all 20 waves of Classic mode, the first 8 Puzzle levels, Relaxed and Normal difficulties, and light and dark appearance — included at no cost.

ONE UNLOCK. EVERYTHING. One single purchase unlocks:

• All 34 Puzzle levels, on every world
• All six worlds (and any future worlds we create)
• Hard, Expert, and Zeckendorf difficulties
• Endless wave mode
• Continuous survival mode
• Game speed control and adjustable wave timers No subscriptions. No ads after you unlock. Yours forever.

THE MATH IS REAL Zeckendorf's theorem proves that every positive integer can be written as a sum of distinct, non-consecutive Fibonacci numbers. That's why every monster in FibDefense can always be solved — and in Zeckendorf mode, the theorem becomes the rules of the game itself: distinct numbers, exact sums, no shortcuts. The math isn't decoration. It's the foundation the entire game is built on.