I accepted slot IU_0023 and saved the review to artifacts/review.json. The name is "Halo Hopper" and the scores are brief 9, silhouette 9, style 10, originality 7.

Checked with code:

• Download and hash: the image downloaded from the URL and its sha256 matches 237a430e…c9440. It is a 512×512 RGB PNG.
• Pixel grid: every one of the 1024 blocks of 16×16 pixels is a single solid colour. So it is a true 32×32 grid scaled up with hard edges, with no anti-aliasing, gradients or blur.
• Palette: the image uses exactly 10 colours. The background is #0c1610, the outline is black, and the other 8 are lagoon, bone, steel, gold, navy, phosphor, cobalt and moss, all from the allowed list.

Judged by looking at the image:

• Species and skin: it's a lagoon-coloured frog with two eye bumps on top of its head and a wide mouth.
• Visor: a steel band with a green and navy lens runs across the face.
• Halo: a gold ring floats above the head.
• UI tee: a bone-white tee carries a small cobalt "U" and moss "I", which is the one allowed logo.
• Layout: there is one front-facing bust, centred, with the shoulders reaching the bottom edge. Every shape has a thick black outline. The background is plain, with no scenery and no other text.

Where I deducted points: originality got a 7 because the face is simple and a bit template-like. That score is my judgement call, not a measurement.

Gaps:

• I didn't compare it against the other Units, so I can't confirm it fits the full 787-piece set.
• I didn't add the separate README the reference mentions, because the task said to write only the JSON file.
• git status showed no changes after writing the file, which suggests artifacts/ is ignored by git. That fits the instruction to leave outputs untracked.