The serpent. A single file of marbles pushed out of the slot toward the sink. Only its rearmost stretch is driven; marbles ahead of a gap stand still until the gap closes.
Bursting. Three or more of one colour touching burst. Where like colours meet across a gap, the front of the serpent draws back to close it — and if that makes three, they burst too: a chain.
The bite. Middle-click, or hold Shift or F and click: the first marble your aim line meets is torn out of the serpent and lands in the launcher as your next shot, and the wound closes by the rule above. The launcher holds 3 fangs a gate. A bite whose wound closes into a burst — an ouroboros — regrows its fang, and so does any chain two deep. On a touch screen, tap the fangs, then the marble; tap the launcher to swap.
Blessings. Ringed marbles carry blessings. Burst one, or bite it and fire it where you choose: the star shatters every marble within 2 widths of where it lands; the backward coil drives the serpent back for 3 s; the hourglass slows it to a crawl for 8 s. A blessing fades from the serpent after 20 s.
Score. A burst pays 10 a marble, plus 100 for each step of chain behind it. A shot through a one-marble gap adds 500, 50 less for each width wider, paid only if its marble bursts. A bitten marble fired into a burst within 2.5 s pays that burst twice.
Streak. From the 5th bursting shot in a row, each pays a bonus that starts at 100 and grows by 10. A shot that bursts nothing breaks it, and so does a desperate bite of the head marble in the embers.
Par time. Clear a gate inside its par time and every second left pays 50, up to 5,000. Unused fangs pay 150 each, and the empty path to the sink is cleansed for 100 every two widths.
The sink. The last 8 widths before the sink glow like embers; there the serpent slows to a crawl, though less in the endless temple. When it is 8 seconds from the sink a heart begins to beat, faster as it nears. One marble in the sink and the gate is lost: its score is forfeit, and you may try it again at once.
Colour and the aim line. Every marble is one of 5 colours, each with its own shape of light inside — a core, bands, a ring of dots, a cross, a ring — so the serpent reads without colour. The aim line and the ghost marble are always drawn and never lie: a shot, and a bite, go exactly where they show.
Relics. Between gates, and after every warden you fell, claim one of three relics. You hold up to 8; to claim another, lay one down, and it can be offered again later. Every relic raises the serpent's speed, and a rarer relic raises it more; once it has sped up, the SPEED pips show how fast it moves and what each relic adds. Skip the three for score, and a sped-up serpent slows a little. Score also buys a reroll, once a draft, or a candle, once a temple. In the first temple a skip pays 1,000, a reroll costs 1,700 and a candle 5,000. Deeper in, a skip's pay is multiplied by the temple's number; a reroll rises to 2,700 and a candle to 8,000 in the fourth. The rite begins with 3 candles, and every swallow snuffs one. Measured: with no relic and the serpent at its top speed, a player who never bites still holds all 24 gates.
Elements. Deeper in, some marbles carry an element — ember, tide, storm or oil — shown by a sigil, never by a colour. Pairs that burst together react: ember and oil make an inferno that burns the next 5 marbles; storm and tide throw an arc that strikes up to 6 lone marbles of its colour; ember and tide rise as steam, and the serpent slows for 6 s. Bite an element out of the serpent and fire it into its partner, and you aim the reaction yourself. Measured: an inferno pays 150, or 180 with an oil in its fire; an arc that strikes three lone marbles into a CHAIN ×3 pays 390.
Wells. In the deeper temples, wells curl every shot that passes them, and the aim line curls with them: it still never lies. A burst from a shot bent 45° pays 100 more, and one bent 90° pays 200. A shot that falls into a well's heart is lost. On the Molten Bridge an iron marble brings the upper lane down onto the lower. Measured: a shot aimed one marble-width wide of a well's heart is bent 36.0° by a lesser well and 70.8° by a greater.
Wardens. Each temple ends in a warden, an armoured serpent. A crown takes two hits and a shield one; a shot that strikes armour cracks it and is spent. A bite strips one armour and costs a fang, and a star, an ember or an inferno cracks every armoured marble it reaches. Breaking a crown pays 500; felling a warden pays 2,000 and unlocks a new relic. Measured: never biting, a player who strikes the armour first fells each warden 20 times in 20, in a median of 59.2, 80.8, 69.0 and 68.5 s.
Coming back. Each gate keeps a record of the marks its clear screen awards and the best score it was held for; from your second run the clear screen names them, and once a gate has a record, a mark not yet in it says NEW. Once gate VI holds, the title offers today's gate: one of the 24 gates with two relics, the same for everyone that day, turning at midnight Taipei time. Try it as often as you like; your best hold is the day's, and every day you play counts. Fell all four wardens and the title opens the gauntlet: the four back to back on two candles, with no relics. Measured: a player who never bites holds today's gate on 365 days of 365, and runs the gauntlet without losing a candle.
Measured, not claimed. A one-marble gap between like colours closes in 0.19 s; the odd marble bitten from between two pairs bursts as an ouroboros worth 290 and regrows its fang 0.28 s later; a player who never bites holds all 24 gates, and each par time is that time plus a quarter; every gate keeps at least 66 % of the serpent in the launcher's line of sight; and in greyscale at half size every pair of colours still differs across at least 14 % of the marble.