Chain Reaction Online

New: 24 forced-win puzzles, six board shapes, correspondence games you can play over days, and a far sharper Expert AI.

Chain Reaction Online is a fast, ruthless strategy game about turning your opponent's board into your own.

Place an orb in any empty cell or one you already own. Fill a cell past its limit and it explodes into its neighbours — capturing them. One well-placed orb can cascade across the entire grid and flip a losing position in a single turn.

Simple to learn. The chain reactions are where it gets interesting.

MODES • Quick Match — get paired with a real opponent in seconds • Correspondence — up to 3 days a turn, play at your own pace • Private rooms — share a 6-letter code and play a friend anywhere • Pass and play — 2 to 4 players on one device • vs AI — four difficulties, from Easy to a genuinely mean Expert • Campaign — 100 hand-built levels with escalating pressure • Puzzles — 24 positions with a win you can force, if you find it • Daily Challenge — one new objective every day • Mid-Game Takeover — drop into a half-played board and try to turn it around

BOARDS THAT CHANGE THE GAME • Six shapes — Classic, Donut, Diamond, Cross, Pillars and Gates • Walls change which cells are corners, so the whole strategy shifts • 5x5, 6x6 and 7x7 grids

COMPETE • Elo rating with 16 tiers, from Newcomer to Ascendant • Challenge any player directly, or rematch a recent opponent • All-Time, Weekly and Takeover leaderboards • Achievements for chains, streaks and comebacks • Track your best chain, win streak and match history

BUILT TO PLAY ANYWHERE • Campaign, AI, puzzles and pass-and-play work fully offline • Results sync automatically when you are back online • Hints when you are stuck — two per game • No ads. No in-app purchases. No account or sign-up needed.

Every orb you place is a threat. Every cell you fill is a risk. Chain reactions do not care whose turn it started on.