NEW EARTH is playable
One session. The frame time cut nearly in half and the stalls eliminated. A character-select screen, creatures that hunt you, melee combat, XP, a quest, and an AI that keeps building the world while you play. And the best part is a bug that turned out to be the theory showing off.
The bug that was actually dark matter
The session started with a red gate. G2 — light deflection — was failing at 30.7% error against the textbook weak-field formula 4GM/c²b. Everything else was green. The obvious move is to hunt for a solver bug.
There was no solver bug. Two things were true instead. First, this world is deliberately strong-field: ψ at the ray's closest approach is ~0.15, and the bend angle is 17.5 degrees. The textbook formula is a linearization that assumes tiny angles; it was being asked a question outside its domain. Second — and this is the good part — the engine world sits in DFD's μ-transition regime. The field gradients here are only ~5–20× the a★ scale, which means μ(x) = x/(1+x) < 1, which means the field decays slower than 2GM/c²r. The planet carries an emergent dark halo. That's not a rendering feature. That's the same mechanism DFD uses to explain galactic rotation curves without cold dark matter, running live in a game engine.
So the fix wasn't to change the engine — it was to make the gate expect what the theory actually predicts: compare the engine against DFD's own exact answer for this world, not against a textbook shortcut that doesn't apply here.
Result: 0.10% error, at a tolerance we tightened from 20% to 10%. The engine reproduces the theory's strong-field, dark-halo lensing to one part in a thousand. All four gates green.
Finding the real frame time
The bench harness we added this session (camera sweeps 360° over 300 timed frames, prints percentiles) told an ugly story at first: 26 ms median with p95 spikes over a full second. The spikes turned out to be measurement contamination — the engine's start-up work was still running inside the timing window. With honest warmup, the worst frame of the run is 22 ms. The one-second-stall class is dead.
The median was real work though, and the profile was surprising. Shading, shadows and ambient occlusion were cheap. The cost was in finding the world in the first place — rays were spending most of their time crossing empty air.
The fix is the kind the engine's own discipline demands: no second copy of the world, everything still comes from the one field. Rays now cross empty air quickly and save their effort for where things actually are, and sky rays finish early instead of burning their whole budget.
Median frame: 29.8 ms → 17.6 ms, measured on the worst case we have (night forest, full scene). Average frame including the old stalls: 85 ms → 18 ms.
It's a game now
Until today you could walk on New Earth and reshape it. Now you can play it. The build opens on a character-select screen: Wanderer (fast), Shaper (bends more of the field per stroke), Warden (iron constitution). Trolls, ogres, and outlaw raiders wander the spawn valley with aggro radii, chase you across the curved surface, and hit hard enough to kill — death sends you back to your bind point, EverQuest-style. Sword swings crit, kills pay XP, levels heal and add vitality. A dwarf named Foreman Duri stands near spawn with a job for you, and the world is carved into eleven named zones that announce themselves as you cross their borders. Every creature walks on the same ground the player does — there is still no second physics system.
The Shaper
The engine now has a resident. Every couple of minutes, The Shaper — an autonomous world-builder running inside the engine — picks a spot near you and raises something out of the world itself: a basalt spire, a stone circle, a ruined wall, a watchtower with a hollow interior and a doorway, a cairn field, a half-buried gate. It builds the same way you do, a little at a time so nothing ever hitches, and its work stays, just like yours. A banner tells you what went up and in which compass direction; walk over and it's simply there, part of the world, diggable like everything else.
This is the seed of the vision: a world that accretes history alongside its players. Today the Shaper is procedural. The way it builds is exactly the interface a smarter mind plugs into next.
Play it
The alpha build exists — macOS on Apple Silicon, single-player. The public play button will go live when the game is done; follow the devlog for the moment it lands. Multiplayer is the next milestone, and it's an infrastructure problem, not an engine one.
Engine version v0.10.140. All four physics gates green. One session, one post — that's the rhythm.