FibDefense: tower defense where the mathematics is the game

A tower defense game built on one rule that changes everything: a tower will not fire if its shot would overkill. Damage values follow the Fibonacci sequence, so winning means arranging towers whose shots sum to exactly an enemy's health. Thirty-four hand-designed levels, on both mobile stores.

The situation

Tower defense is a crowded genre where most entries differ only in theme. The design problem was to find a rule that turns the familiar loop into an actual puzzle without needing a tutorial nobody reads, and then to hand-build enough levels around it to prove the idea holds up past the novelty.

What we built

The whole game comes out of one constraint. A tower only fires when its damage will not exceed what the enemy has left, so an approaching enemy is a number you have to hit exactly, using the towers you have placed and can afford. Because the damage values follow a sequence where each is the sum of the two before it, sequences chain in ways that reward planning and punish placing the biggest thing you can afford. Thirty-four levels were designed by hand rather than generated, because a puzzle with exactly one satisfying solution is not something you get by accident. It ships free with a single unlock, on both stores.

• One rule that turns tower defense into arithmetic under pressure
• Damage values that chain, rewarding planning over spending
• 34 hand-designed levels, each with a real solution
• Free to play with a single unlock, no subscription
• Shipped on both mobile stores

Interface illustrations. Abstracted representations with placeholder content — never client data.

What changed

A genre staple turned into a puzzle game, with a rule a player understands in one round and is still working against thirty levels later.