Super Stacker — Stack Blocks, Beat Real Physics

A free 3D physics block-stacking game built with three.js for rendering and the cannon-es rigid-body engine for physics, stepped at a fixed 60 times per second. You drop blocks one at a time to build a tower as tall as you can, and every block is a real rigid body with gravity, momentum and collisions — not a scripted animation. Lean the stack too far and it can tip and crash for real, exactly like a physical tower would.

Yes, completely free and it runs right in your browser with no install or sign-up — just tap Start Stacking. The 3D scene and physics engine load on demand, and everything about your session stays local until you actively choose to submit a score. There are no paywalled difficulties and no block limit to unlock.

On desktop, move your mouse left and right to slide the hovering block, then click or press Space to drop it. On mobile, tilt your phone like a small steering wheel — the game reads your device's gravity/orientation sensor — or drag the screen instead, then tap anywhere to let go. Both input methods only move the block horizontally, so switching devices doesn't change your strategy.

Your score is simply the number of blocks you land and settle before the tower topples — each successfully stacked block adds one to your count. Landing within a small margin of dead-center on the block below counts as a Perfect, and stringing several Perfects together escalates the combo effects and rising-pitch audio, but it doesn't add bonus points to the final tally. Blocks also get narrower the higher your stack climbs, which is what actually makes bigger scores harder to reach, not the scoring formula itself.

The game tracks two separate thresholds after a block lands: if it settles too far off-center it's simply scored as a miss, but if the topmost block's own position later sinks more than about one and a half block-heights below where it settled, the whole tower is judged to have physically toppled. A block also has to slow down and stay nearly still for roughly a third of a second before it even counts as settled — a still-wobbling block isn't safe yet. Because it's a live physics simulation rather than a fixed rule, two visually similar drops can occasionally resolve differently depending on momentum.

The game runs entirely in your browser — the physics simulation, rendering and scoring never touch a server while you play. Only the nickname and final block count you actively choose to submit are sent to the shared world leaderboard, and nothing else about your session is collected.