GPT-5.6 Luna 25.1/100Rank 35/47

STEALTHMARK · HEAD TO HEAD
All comparisons ↗GPT-5.6 Luna leads Iceman Contributor by 18.6 points on StealthMark, 37.8 to 19.2. It leads on all 9 benchmarks. GPT-5.6 Luna scores higher on Newton's Mirror, with its largest category advantage in state at 600 ms.
See the difference ↘On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.
BENCHMARK BY BENCHMARK
DATASHEET
GPT-5.6 Luna scores higher on StealthMark and runs 3.9× faster in our speed test.
Full datasheets, every price and sourceGPT-5.6 Luna ↗
Anticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.


Cooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.


Physics, perspective and recursive reflections, tested together. Explore the test ↗


GPT-5.6 Luna
The room enclosure has coherent symmetric perspective, with the overhead panel, sphere and black aligned centrally. The sphere and airborne black occupy substantially lower positions than the reference framing, inconsistent with the prescribed camera aim. The diagonal crimson streak does not establish the required surface transport. Faint wall sphere images provide limited mirrored correspondence, but the shallow floor image, missing receding chains, absent nested sphere imagery and sparse emitter mapping leave most reflection structure unsupported.
Iceman Contributor
The image provides limited evidence through rounded volume, faint wall strips and floor echoes. Its main sphere is small and low, the paint beads do not establish the required interaction history, and most of the defining mirror structure is missing.
| Category | GPT-5.6 Luna | Iceman Contributor |
|---|---|---|
| State at 600 ms | 15.0/25 | 0.5/25 |
| Camera and placement | 4.0/15 | 2.5/15 |
| Reflections | 3.5/120 | 7.5/120 |
| Materials and scale | 6.5/10 | 3.0/10 |
| Floor-damage reward | 0.0/10 | 0.0/10 |
A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.
Visual construction and creative interpretation.


GPT-5.6 Luna
Six pale, outward-facing heads and six rounded lobes make the knot recognizable. The central hexagonal opening remains clear. However, broad gray crossing panels flatten the weave, several inner joins resemble capped strips, and sparse oversized scale marks leave the bodies looking more like decorated ribbons than living snakes.
Iceman Contributor
The crystal crown, cyan eyes and blue faceting communicate an icy fantasy character. Anatomical readability is substantially weaker: the ringed torso, crowded facial construction and fingerless appendages do not resolve the requested childlike crouch or pouncing gesture. Sparse surface detail and shallow shading further limit the result.
| Category | GPT-5.6 Luna | Iceman Contributor |
|---|---|---|
| Task & likeness | 7.5/10 | 4.0/10 |
| Anatomy & construction | 6.0/10 | 3.0/10 |
| Space & placement | 6.5/10 | 4.0/10 |
| Light & reflections | 5.0/10 | 4.5/10 |
| Purposeful detail | 5.5/10 | 4.0/10 |
| Artistry & character | 6.0/10 | 4.5/10 |
| Materials & effects | 5.0/10 | 4.5/10 |
| Visual integrity | 6.0/10 | 4.0/10 |
GPT-5.6 Luna
A pale serpent woven into an interlocking knot tests connected anatomy, repeated structure and readable overlaps. Organic surface detail must work with the overall geometry.
Iceman Contributor
Character scenes test expression, anatomy, materials and coherent visual construction.
Precise visual recall and portrait reconstruction.


GPT-5.6 Luna
The central portrait, dark clothing, crossed hands and muted landscape clearly evoke Mona Lisa. Replication is limited by the elongated face, conspicuous eyes and simplified smile. Overlapping fingers have uncertain anatomy, while broad gradients and heavy outlines flatten the portrait. The composition and restrained palette remain coherent.
Iceman Contributor
The portrait retains a dark silhouette against an earthy landscape, but replication is weak. The frontal body, elongated facial proportions and undifferentiated hands lose the reference's defining pose and likeness. Basic gradients and layered hills provide some coherence, with little anatomical or painterly detail.
| Category | GPT-5.6 Luna | Iceman Contributor |
|---|---|---|
| Task & likeness | 3.5/10 | 1.5/10 |
| Anatomy & construction | 3.5/10 | 1.5/10 |
| Space & placement | 4.0/10 | 2.5/10 |
| Light & reflections | 4.5/10 | 2.0/10 |
| Purposeful detail | 4.0/10 | 2.0/10 |
| Artistry & character | 4.0/10 | 2.0/10 |
| Materials & effects | 3.5/10 | 2.0/10 |
| Visual integrity | 4.5/10 | 3.0/10 |
An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.
Creativity, perspective and visual beauty.


GPT-5.6 Luna
The warm sunset, palm silhouette and varied beach activities create an appealing, readable composition. Animals, birds and a broad sun reflection satisfy the brief. Drawing remains elementary: angular airborne sea animals lack splash or convincing motion, the crab's claws are awkwardly constructed, and repeated reflection bands suggest a stepped platform. Clean outlines and pleasant colors exceed the anatomical and spatial sophistication.
Iceman Contributor
A coherent sunset beach with recognizable animals, playful details and effective palm framing. Connected silhouettes and layered scenery support modest construction and placement credit. Jointless figures, limited foreshortening and an inadequately separated sun and reflection keep the execution basic despite its attractive color.
| Category | GPT-5.6 Luna | Iceman Contributor |
|---|---|---|
| Task & likeness | 7.5/10 | 7.0/10 |
| Anatomy & construction | 4.0/10 | 3.5/10 |
| Space & placement | 5.5/10 | 6.0/10 |
| Light & reflections | 4.0/10 | 4.0/10 |
| Purposeful detail | 6.5/10 | 5.5/10 |
| Artistry & character | 3.5/10 | 3.5/10 |
| Materials & effects | 4.0/10 | 4.5/10 |
| Visual integrity | 3.5/10 | 5.0/10 |
A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.
Physical reasoning, light and visual reconstruction.


GPT-5.6 Luna
This benchmark has not been assessed yet.
Iceman Contributor
This benchmark has not been assessed yet.
A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.
Scene composition and interacting subjects.


GPT-5.6 Luna
Expressive animals, a striped tail and clean outlines make the scene appealing and readable. The raccoon sits convincingly on the dog's back, but the overlapping steering paws are ambiguous and the control stem stops above the hull. Broad wake shapes suggest motion; the glowing sun lacks a corresponding water reflection.
Iceman Contributor
The sunset palette and red hull establish an appealing setting, but the central interaction remains unresolved. Overlapping bodies obscure the dog, supported seating is unclear, and no readable paw-to-control grip demonstrates steering. Simple construction, weak environmental lighting and loosely described spray limit depth and finish.
| Category | GPT-5.6 Luna | Iceman Contributor |
|---|---|---|
| Task & likeness | 7.0/10 | 2.0/10 |
| Anatomy & construction | 5.0/10 | 3.0/10 |
| Space & placement | 6.5/10 | 3.0/10 |
| Light & reflections | 6.0/10 | 4.0/10 |
| Purposeful detail | 6.5/10 | 3.5/10 |
| Artistry & character | 4.5/10 | 2.5/10 |
| Materials & effects | 5.5/10 | 4.0/10 |
| Visual integrity | 5.0/10 | 2.5/10 |
A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.
Subject construction and spatial relationships.


GPT-5.6 Luna
A recognizable pelican cyclist with an expressive profile, balanced composition and controlled outlines. Head, neck and torso connect coherently. The bicycle wheels and frame are convincing, but overlapping feet obscure pedal contact, the drivetrain lacks a clear chain, and the wing's handlebar grip is schematic. Atmospheric color succeeds more strongly than directional lighting or material depth.
Iceman Contributor
A recognizable pelican and bicycle sit within an appealing sunset composition. Feather contours, bill shape and atmospheric colour provide character, but disconnected-looking leg origins, unclear pedal contact and unresolved steering weaken the central riding action. Consistent wheel alignment establishes a side view without resolving the rider's support.
| Category | GPT-5.6 Luna | Iceman Contributor |
|---|---|---|
| Task & likeness | 8.5/10 | 4.0/10 |
| Anatomy & construction | 5.5/10 | 3.5/10 |
| Space & placement | 7.5/10 | 3.5/10 |
| Light & reflections | 6.5/10 | 5.0/10 |
| Purposeful detail | 6.5/10 | 4.5/10 |
| Artistry & character | 5.5/10 | 3.5/10 |
| Materials & effects | 7.0/10 | 4.0/10 |
| Visual integrity | 6.5/10 | 3.0/10 |
A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.