The Chain Reaction browser puzzle is a five-level trigger game where one selected source unit emits a discrete tick wave across the 5×5 grid. Each experiment loads with several units already placed, each showing a power value from one to three that defines its Manhattan reach - the number of horizontal plus vertical steps it can cover without diagonal shortcuts. A beginner chooses exactly one source and presses trigger; that source fires on tick zero, every uncleared unit within its range activates on tick one, and the wave then spreads frontier by frontier until either the field is cleared or no new unit can be reached. Clearing every unit on a single field awards 200 points, and finishing all five experiments produces the exact maximum 1,000-point score. The challenge for a new player is not building anything; it is reading power and position together well enough to start a directed cascade that reaches the entire field.
What loads on your first chain reaction screen
A new player opening the Chain Reaction game sees a 5×5 grid holding several round unit cells, each marked with a power number from one to three, surrounded by a Restart button, a Trigger button, and a Next experiment control. Before any wave runs, the screen shows only the product rules: the position of every unit, the visible power value on each unit, and the player's current selection. There is no preview of the future tick list, no correct-source flag, no hidden answer, and no solution index - the board is genuinely deterministic, but those details are not exposed in visible text, accessibility labels, hidden fields, or data attributes until you trigger and observe the result. The five-by-five field stays within a 390-pixel viewport so it works on phone screens, every unit control is at least 44 pixels high, and status updates use live text so screen readers can follow the cascade. Knowing that the screen deliberately hides the solution makes a beginner's first job very specific: learn the rules from the board itself, predict the wave, and only then click trigger.
How to read power and position before you click
Power is the single most important number on the board, and beginners should treat it as Manhattan distance, not as a circular radius. A unit with power two reaches any uncleared cell whose horizontal plus vertical step count from that unit is two or less - so a unit at row one column one with power two reaches row one column three, row three column one, and the diagonal cell at row two column two, forming a diamond of reachable cells, but it does not reach row two column three, which is two right and one down, totalling three steps. Diagonal shortcuts are not allowed, which is the rule beginners forget first. Position matters just as much as power: a high-power unit sitting in the corner can only reach a thin L-shaped wedge, while a moderate-power unit in the middle of the field can reach four arms at once. Reading the board before triggering is therefore a two-pass habit: first scan every power number to identify the strongest sources, then check whether their position can actually hit useful relays instead of dead ends.
| Power value | Manhattan reach | Beginner implication |
|---|---|---|
| 1 | One orthogonal step in any of four directions | Short hop to a single neighbour only |
| 2 | Two orthogonal steps total in a diamond shape | Reliable mid-range relay between distant units |
| 3 | Three orthogonal steps total in a diamond shape | Wide spread when placed near the centre of the field |
Pick a first source and run your first tick wave
For a beginner's first attempt, the goal is to understand how the tick wave behaves, not to memorize a solution. The steps below use the actual rules of Chain Reaction so you can replay them on the first experiment.
- Open the first experiment and leave the field untouched. Spend a moment locating every unit and noting the power number printed on each one.
- Pick a source by reading power and position together. Choose a unit that has at least one other unit inside its Manhattan range - a source that reaches nothing on tick one starts a wave that ends immediately.
- Tap that unit, click it, or use arrow keys to focus it, then press Space to select it. The selection state should change on the unit before you continue.
- Press the Trigger button or press Enter to launch the field. The selected source fires on tick zero, and the units it can reach light up together on tick one.
- Watch the tick recorder on the side of the board. It lists every observed wave as T0, T1, T2, and so on, and cleared units shrink while displaying the tick on which they reacted.
- Compare the recorded ticks with your mental forecast. If the wave stopped before clearing the field, choose a different unit and trigger again - the board resets to its original state, and the failure history lets you repair one bad choice.
- When every unit on the field is cleared, the level awards 200 points and unlocks the next experiment. Repeat for all five fields to land exactly on the 1,000-point maximum.
Beginner mistakes that leave units uncleared
The most common first-run mistake is treating power like a circular radius and forgetting that diagonal jumps cost two steps. The second is choosing the strongest unit on the board and assuming it will reach everything - high power in the wrong corner reaches only a thin wedge of cells. The third mistake is starting on a unit whose range covers no other unit at all, which fires on tick zero and then stops on tick one because nothing else can be reached. The fourth is rebuilding the wave as a single chain in your head: chain reaction fields are not single chains, they are simultaneous frontiers, so several units activated on the same tick form one frontier and only that frontier emits during the following tick. A branch that fans out into two regions on tick two is more powerful than a long single chain that ends in a dead end. Finally, beginners often press the same failed source twice expecting to spend two mistakes - the system deduplicates identical failed triggers, so a double press does not consume a second mistake, but a genuinely different second failed source ends the run.
How the five experiments grow harder
The five chain reaction experiments share the same 5×5 grid, the same power range from one to three, and the same Manhattan reachability rule. Difficulty grows through placement, not through rule changes. The first level is a short three-unit relay that almost any beginner clears with a moment's thought. The second adds longer fuses where a mid-power unit has to bridge two distant neighbours. The third introduces a corner-to-corner handoff that must bridge between opposite quadrants. The fourth asks the source to bloom in four directions at once, which means the trigger must reach multiple relays together when the wave starts. The fifth and final experiment is a multi-branch surge where the trigger fans out into several simultaneous frontiers, and the central question is which existing unit can start a directed cascade that eventually covers the whole field. Because the simulation is fully deterministic, you can compare your mental forecast with the exact recorded tick groups and pinpoint exactly where an unsuccessful chain stopped.
| Experiment | Beginner focus | Key challenge |
|---|---|---|
| 1 | Three-unit relay | Confirm the tick rule and Manhattan reach |
| 2 | Longer fuses | Bridge two distant neighbours with one mid-power unit |
| 3 | Corner-to-corner handoff | Pick a relay that crosses quadrants |
| 4 | Four-way bloom | Source must reach multiple relays together to bloom outward |
| 5 | Multi-branch surge | Simultaneous frontiers and dead-end avoidance |
If you want a deeper walkthrough of one of these cascades, the Chain Reaction tick wave guide covers the same triggering rules in more detail.
Score, repair, and the exact 1,000-point finish
Clearing every unit on a single experiment awards exactly 200 points, and five full clears produce the exact maximum score of 1,000. A trigger that leaves any active unit earns zero points for that field, but it does not lock the run. You may repair one failed source by selecting a different unit and triggering the field again, and the failure record is cleared the moment a corrected source succeeds. The same failed source pressed twice is deduplicated, so it costs only one mistake. A second genuinely different failed source, however, closes the run, so beginners who are unsure about their second attempt should think carefully before committing. Status updates with live text report every point change, the current selection, and the experiment number, so you always know how close you are to 1,000. Because everything runs locally in the browser and no score, mistake, or progress is uploaded, you can reset and replay any field as many times as you like.
Mouse, touch, and keyboard controls for beginners
A beginner can play chain reaction with any input style that fits the device. On a phone, tap a unit to select it, then press Trigger selected unit; the game uses native unit buttons that are at least 44 pixels high and the field fits inside a 390-pixel viewport. On a desktop, click a unit to select it and click Trigger to run the field. Keyboard play is scoped to the reaction field: focus any unit with the mouse, then use the arrow keys to move through the available units in spatial order, press Space to select, and press Enter to trigger. Restart, Trigger, and Next experiment keep their normal button behaviour when they hold focus. Touch, mouse, and keyboard inputs are atomic - an invalid key, a stray click on an empty cell, or a misfire on a control that is not focused produces no change to the field. The whole experience doubles as a compact reasoning break and a visual introduction to directed reachability, which is the underlying skill you are practising every time you read power and position together.