Online Tetris Game

A falling-block stack becomes difficult long before it reaches the ceiling. Uneven columns create holes that later pieces cannot fill from above, while a flat surface preserves several placement choices. Most good decisions protect future space rather than maximizing the current drop.

Seven tetromino shapes arrive one at a time. Completing every cell in a horizontal row clears that row and lowers the stack. Clearing several rows with one piece scores more than clearing them separately, but holding a deep well for a four-row clear also increases the chance of blocking the board while waiting for the needed shape.

Ghost piece

A landing outline shows where the active shape would stop if dropped without further sideways movement or rotation.

Hold slot

One active shape can be set aside or swapped, but the hold action becomes available again only after a piece locks.

Next queue

Upcoming shapes support planning across several placements instead of reacting to the active piece alone.

Gravity gets faster as cleared lines raise the level. Soft and hard drops trade planning time for placement speed and a small row-based score. Rotation may shift a piece away from a wall or stack when its first rotated position does not fit, so a tight placement can still be legal without occupying the exact pivot position first expected.

Piece order matters enough that two scores are not automatically comparable. A seed fixes the shuffled seven-piece groups, while entry speed and the ghost and hold assists define the challenge. Keep all four conditions unchanged when testing whether a different placement plan improved the run.

This classic-inspired ruleset uses its own scoring, gravity presets, and rotation offsets. It should be judged by the rules documented here rather than assumed to match a particular commercial release or competitive guideline.

How to Use This Tool:

Set the opening pressure and assists before the first piece appears; those choices remain fixed for the run.

1. Choose Entry speed, enter a Run seed, and decide whether to keep the Ghost piece and Hold slot.
2. Start the run, then use Left and Right to position, Up or Z to rotate, Down to soft drop, Space to hard drop, and C to hold. The touch pad exposes the same placement actions.
3. Watch the next three pieces and the height of the stack before committing a hard drop. Pause with P when you need to stop gravity and the active clock.
4. Review Score, Lines, Level, Tetris clears, and Best combo when the stack tops out or you end the run. Replay the same seed with the same assists for a direct practice comparison.

Interpreting Results:

Lines measures board progress, while Score also rewards multi-line clears, consecutive clearing pieces, and drop distance. A higher score with fewer lines may come from hard drops or a few large clears rather than a longer surviving stack.

• Level rises at 10, 20, 30, and subsequent ten-line totals. The new level affects the clear that crosses the boundary.
• Tetris clears counts pieces that remove four rows at once; it does not include other multi-line clears.
• Best combo counts the longest run of consecutive pieces that each cleared at least one line. A piece with no clear resets the current combo.
• A topped-out ending means a new or locked piece could not fit below the ceiling. Compare the summary only against runs with the same seed, speed, ghost setting, and hold setting.

Technical Details:

The playfield is 10 cells wide and 20 cells high. Shapes arrive in seeded groups containing one each of I, J, L, O, S, T, and Z, shuffled before being appended to the queue. This prevents a shape from disappearing indefinitely while preserving a repeatable order.

Rule Core

A piece may move or rotate only when every resulting cell stays inside the horizontal bounds, below the floor, and outside locked cells. Rotations test a short ordered set of horizontal and vertical offsets; the first legal position wins, and the rotation is rejected when none fits.

Formula Core

A clearing piece combines the base value for the number of rows, a consecutive-clear bonus, and the level after those rows have been added.

P is the points from the clear, c is rows cleared by that piece, q is the current consecutive-clear count, and v is level. Base values B are 100, 300, 500, and 800 for one, two, three, and four rows.

R is total lines, g is gravity time in milliseconds, and p is the preset interval in 50 ms ticks: 16 for Slow, 12 for Medium, 8 for Fast, and 5 for Sprint. Gravity never becomes faster than one 50 ms tick.

The ghost is a projection only; it does not change collision or scoring. The hold setting changes which actions are available, and the seed fixes queue order, so both belong with entry speed in any fair run comparison.

Worked Examples: