Restructure Tetris Attack Stage Clear from "clear all target panels" to a
multi-stage round system with a sliding boundary line.
Gameplay changes:
- Each character now has 5 stages instead of a single match
- A CLEAR line appears after a set number of rows rise, then rides the
stack upward; the objective is to clear everything above it
- Clearing a stage advances to the next: same board, faster speed, fresh line
- Stage progress is saved to localStorage; characters unlock sequentially
- Added a stage select screen with progress squares per character
Logic changes:
- Replaced `targetsTotal` with `clearLine` tracking and `countAboveLine`
- Added `advanceStage()` to resume play on the same stack one speed level higher
- Win condition now checks `countAboveLine() === 0` instead of target count
- Removed `target` flag from panels; panels below the line are irrelevant
- Continuous speed ramp via fractional `speed` per stage
UI changes:
- Clear line drawn as a pulsing bar with "◀ CLEAR" label outside the board
- "CLEAR LINE!" announcement on appearance, "STAGE N CLEAR!" banner on win
- HUD shows stage number instead of panel count
- Game over offers "Retry Stage", "Stage Select", or "Menu"
Asset changes:
- Backgrounds renamed to `background-{hero}-r{stage}.png` (5 per character)
- Lazy-load backgrounds per round instead of preloading all 30 images
- Updated tetrisattack.json with `stagesPerRound`, `stageSpeedStep`, and
per-character `clearLineRows`
Tests:
- Rewrote stage clear soak tests for the new mechanic
- Added stage round progression, speed ramp, and board preservation tests
Brian Fertig
08d23f9613