STRATA

Boulder Dash with chain scoring. Dig, undermine, cascade — engineer a falling-rock combo that takes out every enemy in one stroke.

Objective

You're a tunneling drone burrowing through a fractured mineral vein. Each cave has a gem quota — collect it before the timer runs out, then reach the exit. Avoid falling boulders, avoid enemies, and learn to weaponize gravity. Crushing enemies with a falling boulder isn't just allowed — it's the scoring core. Twelve hand-designed caves, plus a procedural Daily Drift seed mode once you're ready for endless.

Controls

Input	Action
← ↑ ↓ → (or WASD)	Move & dig in that direction
Hold left or right at a boulder	Try to push it; succeeds with some probability per attempt
Swipe	On touch, swipe any direction; one drag can chain turns
Space / tap	Start, advance "READY", move to next cave
P	Pause / resume
R	Restart the current cave (costs a life)
D on title	Start Daily Drift — endless procedural caves on today's seed

How it works

• Dirt — the ochre fill. Walk through to clear it; dug paths stay open. Most of the cave is dirt.
• Boulders — the slate-grey rocks. A boulder sitting on dirt or another solid stays put. The moment its support disappears, it falls. Boulders falling on your head kill you instantly.
• Rolling — a boulder resting on top of another boulder, a gem or a steel wall will roll off if the tile to either side and the tile diagonally below are both empty. The same rule applies to gems — that's how cascades start.
• Pushing — walk horizontally into a boulder. If the tile beyond it is empty, you'll shove it across (eventually — the heavy thing pushes back). You cannot push vertically.
• Gems — the cyan diamonds. +100 each, and count toward the cave quota. The exit only unlocks once you've collected the quota.
• Bugs — the red crawlers. They patrol clockwise around walls. Touch one and you die. Crush one with a falling boulder and it explodes into a 3×3 cloud of gems.
• Butterflies — the purple flutterers. They patrol counterclockwise. Crushed butterflies explode into a 3×3 cloud of diamonds, worth +200 each.
• Magic wall — the violet pulsing strip. The first boulder to fall through it activates the wall for a fixed time window; while active, every boulder falling through is transformed into a gem two rows below (and every gem becomes a boulder). It's a one-shot per cave — spend the window wisely.
• Amoeba — the magenta blob. It slowly spreads into adjacent empty/dirt tiles. If you contain it before it reaches its growth cap, it crystallizes into gems. If it overgrows, every cell hatches into a bug. The HUD meter shows growth vs. threshold.
• Exit — closed and dim until quota is reached, then it pulses green. Step in to clear the cave and score a (timeLeft × 100) bonus plus a small cave-clear bonus.
• Lives — 3 per run. A death restarts the current cave. Score earned in failed attempts is preserved.

Chain scoring

Every time a falling boulder crushes an enemy, you start (or extend) a chain. The chain counter ticks up for every crush that happens before the cascade settles. When everything finally rests, the chain's peak size becomes a squared multiplier on every gem and diamond produced by the chain — points × chainSize².

• Chain ×1: 100 per gem, 200 per diamond. Default.
• Chain ×2: 400 per gem, 800 per diamond.
• Chain ×3: 900 per gem, 1800 per diamond.
• Chain ×4: 1600 per gem, 3200 per diamond.
• Chain ×5: 2500 per gem, 5000 per diamond. And it keeps going.

The reward grows quadratically. A four-link cascade through butterflies easily out-scores a clean run. Floating ×N CHAIN! popups confirm every link; the audio pitch climbs with chain depth.

Scoring

• Gem: +100 on pickup (plus the chain multiplier the gem inherited at spawn, if it came from a crush).
• Diamond: +200 on pickup; only spawned by crushed butterflies.
• Bug crushed: pays a 3×3 gem cloud at (100 × chainSize²) each.
• Butterfly crushed: pays a 3×3 diamond cloud at (200 × chainSize²) each.
• Cave-clear bonus: +(25 × cave number) on stepping into the exit.
• Time bonus: +(timeLeft × 100) at exit. Speed pays.
• Amoeba crystallized: every cell becomes a gem — potentially a huge pickup.

Strategy

• Read the layout before you dig. Once a boulder falls, you can't un-fall it. Plan the cascade in your head: which boulder is on dirt? Which sits on another boulder ready to roll? Where will a chain detonate?
• Never stand under a boulder. Even if it's currently at rest — one tile of dug dirt can change that. The single most common death is being directly below your last action.
• Bait enemies into kill zones. Bugs walk clockwise around walls; butterflies counterclockwise. Pick a corridor under a stack of loose boulders and let the patrol drift into it. Then undermine.
• Multi-crush is the score. A chain of three crushed butterflies in the same cascade is roughly 9 × 200 × 9 = 16,200 points — before you collect a single diamond. Look for layouts where multiple enemies cross under the same boulder column.
• The magic wall is a multiplier window. The wall activates on the first boulder that falls through it, then runs on a fixed timer. If you can dump a stack of boulders through it during the window, every one becomes a free gem. Don't waste the window on a single drop.
• The amoeba is a clock. If you ignore it, it overgrows and hatches bugs. If you wall it in, it crystallizes into gems — possibly enough to clear the quota by itself. Don't leave it alone, don't panic-clear it — box it in.
• Boulders can roll back. If you push a boulder onto another boulder and the diagonal is empty, your push will roll into a fall. Useful for triggering a chain — or for accidentally killing yourself.
• Watch the timer. When it drops below 30s the HUD turns warning-red and the time bonus shrinks fast. If you've hit quota, run for the exit even if score is on the table.
• R restarts the cave. If you've botched a cave layout beyond recovery — rolled the wrong boulder, walled yourself in — press R. It costs a life but saves the run.

Daily Drift

From the title screen, press D instead of Space. Daily Drift uses today's UTC date as a single shared seed — everyone playing today gets caves derived from the same string, but the caves keep coming endlessly with rising difficulty. The leaderboard ranks total score; the run ends when you're out of lives.

Play STRATA →