Colour Rush is a flood-fill puzzle game played on a 12×12 grid of coloured cells. Starting from the top-left corner, you claim the entire board by picking colours one turn at a time, expanding your flooded region outward to every adjacent cell that shares the colour you choose. You have exactly 25 moves to cover 100% of the grid. There is nothing to download, no account to create, and the game is completely free to play in any modern browser on desktop, tablet, or mobile.

The challenge is deceptively simple on the surface but rewards careful forward planning. Picking the colour that grabs the most cells on the very next turn feels intuitive, but that greedy approach often splinters the board into awkward isolated clusters that become costly to mop up later. The strongest players think two or three moves ahead, asking not just "which colour gains the most right now?" but "which colour best positions me for the two moves that follow?" Targeting large contiguous colour clusters — especially those that bridge multiple zones of the board — is the key to clearing the grid with moves to spare.

Part of the enduring appeal of flood-fill puzzles is the satisfying moment when a single well-chosen colour pick causes a cascade of territory to snap into your flooded region all at once. Because every game generates a fresh random board, that moment of insight never grows stale — each new grid presents a unique spatial challenge to unravel. Players who return for multiple sessions quickly build an intuition for reading colour distributions at a glance and spotting the highest-leverage move without exhaustive calculation. The Best Spare metric gives you a persistent personal benchmark to beat, making every session feel meaningful even when the board refuses to cooperate.

When the game loads, the 12×12 grid is filled with six colours distributed at random. Your flooded region begins as a single cell in the top-left corner, shown with a subtle brightness highlight to indicate which cells belong to you. Below the grid sits a row of six colour-picker buttons — one for each of the colours on the board. Click any button (or press keys 1 through 6 on your keyboard) to select that colour: your entire flooded region instantly repaints to the chosen colour, then expands outward to absorb every cell that was already adjacent to your territory and matches the new colour. The move counter in the stats bar decreases by one, and the progress bar updates to show what percentage of the board you now control. Repeat until you hit 100% coverage (a win) or exhaust all 25 moves (a loss). A results overlay then appears displaying your outcome and, on a win, how many moves you had to spare.

Every new game generates a fresh 12×12 grid by assigning one of six colours to each of the 144 cells independently at random, giving a roughly even distribution across the board. The flood region grows by contiguous adjacency — up, down, left, and right only, never diagonally. This means a cell that is only connected to your territory via a corner does not get absorbed; it must share a horizontal or vertical edge with a flooded cell. This rule has a significant strategic implication: long, thin colour strips that run diagonally away from your expanding region can be surprisingly expensive to capture and are worth targeting early before they become isolated. For players who prefer speed over precision, keyboard shortcuts 1 through 6 map directly to the six colour buttons from left to right, removing the need to move the cursor between the grid and the picker after every move.

Colour Rush uses a single personal metric called Best Spare, displayed in the stats bar above the grid. It records the highest number of moves you still had remaining at the moment you successfully flooded 100% of the board. For example, if you complete the board on your 18th move, you had 7 moves unused — your Best Spare is 7. A higher Best Spare means a more efficient solution. If you run out of all 25 moves without reaching full coverage, no spare is recorded for that attempt and your existing best is preserved. The score is written to your browser's localStorage automatically the moment you win, so it persists across browser sessions on the same device without requiring any account or login. The stat display shows a dash until you record your first successful clear.

Each session of Colour Rush is a self-contained two-to-three minute puzzle with a clean binary outcome — you either flood the whole board or you fall short. That compactness makes it ideal for a quick mental break without the open-ended time commitment of longer games. The Best Spare metric supplies a persistent personal challenge: once you know you can clear the board, the interesting question becomes how efficiently you can do so, and shaving that spare count upward session by session gives a genuine sense of progression. Because the grid is randomly generated every time, previously memorised layouts offer no advantage, and the puzzle stays fresh indefinitely. Beyond entertainment, Colour Rush quietly trains spatial reasoning and forward planning — skills that transfer usefully to a wide range of real-world problem-solving contexts — all in a low-stakes, enjoyable format that requires nothing more than a browser.