Yes, you can play Flood It without downloading — the game runs entirely in your browser, requires no installation, no account, and no remote game service. The Lizely Flood It page hosts an original deterministic 5-by-5 color-flood puzzle that uses a fixed, audited starting board and an independently proven eight-move minimum, so every session behaves identically and every solution can be checked before you commit. The board contains 25 tiles drawn from four colors (Blue, Coral, Gold, and Teal) and each tile carries a letter so the puzzle stays usable when similar hues are hard to tell apart. The flood operation recolors the entire region connected to the top-left tile by orthogonal paths, while matching diagonal neighbors stay visually close but never join the flood. That keeps the rule simple to state but challenging to optimize: route your recoloring choices so the controlled region sweeps the entire grid inside the eight-move ceiling, then press Check board for exactly 1,000 points.
How to Play Flood It in Your Browser Without Downloading
- Open the Flood It page in any modern browser — nothing installs, no extension is needed, and no permission prompt appears.
- Look at the 5 by 5 grid: each tile shows one of four colors (Blue, Coral, Gold, or Teal) and a letter label (B, C, G, or T). The top-left tile is the seed of your controlled region.
- Choose a color different from the current top-left color using a color button, the number keys 1 through 4, or the arrow keys plus Space.
- Watch the flood expand: every tile connected to the top-left by a same-color orthogonal path changes to the chosen color and pulls in any matching neighbors.
- If a move turns out to be weak, press Delete or Backspace to undo the latest color; the board replays deterministically from the original arrangement.
- Keep expanding until all 25 tiles form one connected monochromatic region, ideally inside the eight-move limit.
- Press Enter or click Check board. A fully flooded board checked at or before move eight earns exactly 1,000 points; an unsolved board after eight moves records a mistake.
The Flood Rule: How the Controlled Region Expands
The core mechanic follows the standard color-flood definition described in the formal complexity paper on flood filling games and in Simon Tatham's portable Flood documentation. On every move, you pick one of the four displayed colors. The implementation runs a breadth-first flood from the top-left index, recolors every tile that is currently the same color as the seed and reachable by orthogonal steps, then lets the region absorb any tile already showing the newly chosen color if it touches the region edge-to-edge. Every controlled tile is outlined on the board so expansion is not communicated by color alone.
Only horizontal and vertical neighbors count. Two tiles that share only a corner are visually close but are not connected for flooding, which is a deliberate departure from casual assumptions about "adjacent" squares. The controlled region may bend around the board, may contain many tiles, and may even form a non-rectangular shape, but every tile inside it always shares a same-color orthogonal path back to the top-left seed. Choosing the region's current color is disabled because it would not alter the board and is not a meaningful move under the formal definition.
Controls: Mouse, Touch, and Keyboard Options
The interface is designed so you can play with a pointer, a finger, or the keyboard alone. Four large color buttons sit below the board; each one names the color, shows whether it is the current top-left color, and exposes its role to assistive technology. On a touch device, tapping the same buttons is identical to clicking them. The layout fits a 390-pixel viewport without horizontal scrolling, so the game stays usable on a phone, and the 44-pixel color buttons leave plenty of room for accurate taps.
Keyboard play is fully complete. The arrow keys cycle the color cursor; Space chooses the selected color; the number keys 1 through 4 choose Blue, Coral, Gold, and Teal directly. Delete or Backspace undoes the latest color, and Enter triggers Check board. Holding a key does not accidentally consume several moves, because repeated keydown events are ignored after the first one. The shared game shell also exposes Restart, the local best score, and the double-Escape boss key, so an unexpected visitor can be covered by a spreadsheet-style view in a single gesture.
Why the 8-Move Limit Is Proven, Not Guessed
The starting board is published as the row-major sequence 01231 / 11320 / 20231 / 32102 / 13023, where the digits 0, 1, 2, and 3 stand for Blue, Coral, Gold, and Teal respectively. That means every run starts from the same arrangement: five Blue tiles, seven Coral tiles, seven Gold tiles, and six Teal tiles, with all five rows distinct. Restart restores this exact board, so behavior can be audited rather than depending on an unrecorded random seed.
An independent breadth-first search treats each complete board coloring as a state. From every state it tries each of the three colors different from the current top-left color, performs a separately written flood operation, serializes the result, and visits each distinct board only once. That search finds 415 reachable boards; no solved board appears at depths zero through seven, and the first monochromatic board first appears at depth eight. A second independent enumeration then checks every legal color sequence of exactly eight moves and finds exactly three minimal winning sequences, which the game accepts rather than comparing your play against a single memorized answer.
| Route | Color sequence (8 moves) | Length | Verified minimum |
|---|---|---|---|
| Route A | 1-0-2-3-1-0-2-3 (Coral, Blue, Gold, Teal, Coral, Blue, Gold, Teal) | 8 | Yes |
| Route B | 1-3-2-1-0-2-3-1 (Coral, Teal, Gold, Coral, Blue, Gold, Teal, Coral) | 8 | Yes |
| Route C | 1-3-2-3-1-0-2-3 (Coral, Teal, Gold, Teal, Coral, Blue, Gold, Teal) | 8 | Yes |
Scoring, Mistakes, and the 1,000-Point Finish
Check board follows a clear two-strike contract. If the board is unsolved and fewer than eight moves have been made, the check reports an incomplete attempt and does not add a mistake, which makes early inspection free. At eight or more moves, an unsolved board is a completed limit failure: the first such check records one mistake but keeps the board and Undo active, while a second such check deadlocks the run until Restart. This separates harmless probing from a genuinely exhausted attempt.
A monochromatic board earns exactly 1,000 points only when checked at or before move eight. There is no speed bonus, no move deduction, no random modifier, and no hidden partial credit. Both completion and deadlock are terminal: color choices, cursor movement, undo, and repeated checks all stop changing state, which prevents score farming and gives automated browser checks a stable result. Restart begins a fresh run with zero moves, zero mistakes, zero score, and Blue selected.
Tips for Clearing the 5x5 Board in Eight Moves
Because the board is fixed and published, you can study it before committing to a sequence. Count which color dominates the corners and the edges, since those positions absorb most quickly. The single concrete anchor for the flood rule is the very first move: starting from Blue at index 0, choosing Coral recolors that tile and connects it to the Coral tiles immediately to its right and below, then continues through their orthogonally connected Coral neighbor, leaving indices 0, 1, 5, and 6 controlled while a separate Coral tile elsewhere stays outside until a later expansion reaches it. That single transition illustrates why the choice of seed color matters — it dictates which islands join the flood and which stay isolated.
A practical routine is to sketch three candidate routes from the verified winning sequences, undo any weak opening, and aim to check the board before the eighth move. If your first attempt fails the limit, undo one or more colors, replay the shorter history deterministically, and try a stronger sequence — Undo replays the remaining history from the original board rather than from a hidden snapshot, so you do not need to start over from scratch. If you are looking for another browser-only puzzle with the same no-download convenience, the Play Hangman Without Downloading guide covers a comparable instant-play setup with deterministic scoring.
Why This Flood It Stays Auditable and Private
All rules and state transitions run locally in the browser. The game uploads no board history, requires no account, calls no remote game service, requests no device permission, and introduces no package dependency. The starting board is published, the move limit is proven, and the three minimal routes are enumerated, which means you can verify every claim by hand or by running your own breadth-first search against the documented state graph. A 1,000-point result means only that this one disclosed fixture was completed within its proven minimum limit; it does not measure intelligence, vision, attention, or any educational ability, so treat it as recreational strategy practice rather than a diagnostic assessment.