OP here. You're the second person to say this. I cut my teeth on SD 1.5 - so I'm rather intimately familiar (for better or worse) with the level of prompt craft necessary depending on the model.

I feel like the FAQ section isn't displayed prominently enough:

How are the prompts written?

  In addition to giving models several attempts to generate an image, we also write several variations of the prompt to ensure that models don't get stuck on certain keywords or phrases depending on their training data. For example, while hippity hop is a relatively common name for the ball riding toy, it is also known as a space hopper. We try to use both terms in the prompts to ensure that models are not biased towards one or the other.

  Prompts for Hunyuan were attempted in both Chinese and English with and without Image Optimization.

Additionally when you see a prompt like "Turn on the lights" - the idea is to actually go beyond direct prompting commands - we're actually probing the capabilities of a truly multimodal LLM. It's a prompt that would spectacularly fail in more traditional models (such as SDXL).