Block Cascade: a free online falling-block puzzle game
Block Cascade is a free falling-block puzzle game that runs entirely in your browser. Ten columns, twenty visible rows, and seven piece shapes dealt from a seven-bag randomizer, with a ghost piece, a hold slot and a three-piece preview queue. Controls are the arrow keys to move and soft drop, Z and X to rotate counterclockwise and clockwise, Space to hard drop, and C to hold; on a phone you swipe to move, tap to hard drop and use the on-screen rotate button. There are 15 speed levels, one every ten lines. The whole page weighs about 28 KB with roughly 18 KB of gzipped JavaScript, it runs offline after the first load, and no account required: nothing is uploaded, and your best score stays in this browser.
How to Play
- Pick a mode on the right - Marathon, Sprint or Zen - then press Enter or the Start button to drop the first piece.
- Move the falling piece with ← and →. Hold a direction and it auto-shifts after the DAS delay, repeating at the ARR interval.
- Rotate with Z counterclockwise and X or ↑ clockwise. If the rotation would overlap a wall or the stack, wall kicks try five offsets before the rotation is refused.
- Press ↓ to soft drop for one point per row, or Space to hard drop for two points per row and lock immediately.
- Press C to move the current piece into the hold slot and bring the held piece back out. You get one swap per piece.
- Watch the translucent ghost outline at the bottom of the board: it shows exactly where the piece will land.
- Fill a full row of ten cells to clear it. One line scores 100, two score 300, three score 500 and four score 800, all multiplied by your level, with a 50 percent bonus for back-to-back four-line clears and a rising combo bonus for clearing on consecutive pieces.
- Every 10 lines raises the level and speeds up gravity, through 15 levels. Pause any time with P or Escape, and restart with R.
Features
- Tunable handling. DAS from 40 to 300 ms and ARR from 0 to 100 ms, with an adjustable soft drop rate. Defaults are 150 ms DAS and 30 ms ARR.
- Input decoupled from rendering. The simulation and the input repeat timers run on a fixed 5 ms step, so handling feels identical at 60 Hz and 144 Hz.
- 500 ms lock delay with a 15-move reset cap. You get time to slide and rotate a piece into place, but you cannot stall forever.
- Wall kicks. Every rotation tries five offsets, with a separate table for the line piece, so tucks and spins land where you expect.
- Ghost piece, hold slot and a three-piece next queue, all fed by a seven-bag randomizer so every shape appears once per bag.
- Three modes. Marathon through 15 levels, Sprint over 40 lines against the clock, and Zen with no game over.
- Line-clear flash, row collapse and a combo counter that pops, plus a subtle board shake on a four-line clear. All of it is disabled when your system asks for reduced motion.
- Local records. Best score, best line count, best Sprint time and total games played are kept in localStorage on this device only.
- Works offline. A service worker caches the page on the first visit, so later visits load with no network at all.
- Keyboard accessible. Every control is reachable by Tab with a visible focus ring, and score changes are announced to screen readers.
Frequently asked questions
Is Block Cascade free to play?
Yes. Block Cascade is completely free, with no paid tier, no advertising and no in-game purchases. Open the page and the game is ready; there is nothing to unlock and nothing to buy.
Do I need an account or a download?
No. There is no sign-up, no login and no installer. The game is one HTML page plus a small amount of JavaScript, and it registers a service worker on the first visit so it runs offline after the first load. Your best score, best line count and total games played are written to localStorage in your own browser and are never sent anywhere.
What are the controls?
On a keyboard: Left and Right arrows move the piece, Down arrow soft drops, Z rotates counterclockwise, X or Up arrow rotates clockwise, Space hard drops, C holds the current piece, P or Escape pauses, and R restarts. On a touch screen: swipe left or right to move a column at a time, swipe down to soft drop, swipe up or tap the board to hard drop, press and hold to swap the hold slot, and use the on-screen Rotate button.
Can I change the DAS and ARR handling?
Yes. DAS (the delay before a held direction starts auto-shifting) defaults to 150 ms and can be set between 40 and 300 ms. ARR (the interval between auto-shift repeats) defaults to 30 ms and can be set between 0 and 100 ms, where 0 slides the piece straight to the wall. Soft drop speed is adjustable too. Input is polled on a fixed 5 ms simulation step that is separate from the render loop, so your handling settings behave the same on a 60 Hz and a 144 Hz display. Your choices are saved in localStorage.
What is the difference between Marathon, Sprint and Zen?
Marathon is the endless mode: it runs through 15 speed levels, gaining one level every 10 lines, and ends when the stack tops out. Sprint is a race to clear 40 lines as quickly as possible, and your fastest time is stored on this device. Zen has no game over at all; if the stack reaches the top, the four highest occupied rows are cleared away and play continues, so you can practice placements without pressure.
How was this game made?
Block Cascade was generated from a single prompt on Quodara (https://quodara-ai.com), an AI agent platform that turns a prompt into a deployed web app. The game logic, the rendering, the styling, the static server and this page were all written in one build and deployed to this domain. You can read the prompt and the build on the case page at https://quodara-ai.com/showcase/block-cascade/.
About this build
Block Cascade was generated from a single prompt on Quodara and deployed on 2026-08-21. The delivered page weighs about 28 KB in total, of which roughly 18 KB is gzipped JavaScript, with no framework and no third-party runtime dependencies. Everything you see - the rules engine, the canvas renderer, the handling model and this copy - came out of that one build rather than a template. The prompt and the build write-up are on the Block Cascade case page.