PuruPuru: Pull It Along

The developers describe how their game uses AI generated content like this:

Parts of the game's program code were written with the help of AI coding assistance, under the direction and review of the developer. The store page text and its translations were also drafted with AI assistance and reviewed by the developer. Some of the music was created with an AI music generation service (Suno), selected and adjusted by the developer. The remaining music, artwork, and sound effects are procedurally generated by the developer's own tools - no AI image generation models were used. The game does not generate any AI content during gameplay.

Required on Steam store pages since 2024. It covers content that ships in the game, on its store page or in its marketing — Valve does not require a disclosure for AI tools used during development, so this says nothing either way about how the game was made. Check it on Steam.