Unpredictable Block Puzzle

Beyond the classic falling-block rules, every three cleared lines triggers a random twist event: a gravity surge that makes pieces plummet, mirror mode that flips your left/right controls, a golden block that clears a 3×3 zone, a bomb block that detonates a cross, a permanent speed shift, or bonus lines that double your next clear's points. No two games play the same.

Host creates a room and shares the code; your friend joins. The host starts a "race to 20 lines" — both players get the exact same piece sequence (drawn from the same seed), so it's a pure test of speed and strategy. Your opponent's board and score appear live in the side panel. First to 20 lines wins, or top out first and you lose.

Arrow keys (or WASD) move and rotate: left/right to move, up to rotate, down to soft-drop. Space does a hard drop, C holds a piece for later, and P pauses. On mobile, a full on-screen control pad appears under the board. In mirror mode your left/right controls are temporarily flipped — read the banner and adapt!

Golden blocks land with a 3×3 burst that vaporizes everything around their center (worth 150 bonus points). Bomb blocks detonate a cross-shaped explosion (100 points). They drop when the corresponding twist event is active — the banner tells you which one is coming so you can position for maximum destruction.

Clearing 1 line scores 100, 2 lines 300, 3 lines 500, and a 4-line Tetris scores 800. With the Bonus Lines twist active, your next clear pays double. Soft-dropping also adds a point per cell. Your level rises every four lines, which speeds up the pieces until the twist events start shaking things up.

Yes — both players receive the identical piece sequence generated from a shared seed, so no one gets an easier run. Each player's board is simulated locally (zero lag on your own pieces), and scores and boards sync between the two browsers so you can see how close the race is.

Single-player mode is 100% offline with no data sent anywhere. Online mode uses direct peer-to-peer WebRTC (PeerJS handles only the handshake), so your boards never pass through a server, no account is needed, and nothing is stored or tracked.