At Stripe, we built Markdoc to solve many of the issues mentioned!

https://stripe.com/blog/markdoc

This feels like Markdown + Liquid.

I wrote quite a bit about Fluid, which is the C# implementation of Liquid. https://deanebarker.net/tech/fluid/

Nice. But reminds us that most templating languages support markdown by default.

Very cool!

This is so transparent and has great advice if you read it carefully. Thanks for sharing!

This is possible! Check out https://markdoc.io/docs/nodes#customizing-markdoc-nodes

Incredible

Type in Up, Up, Down, Down, Left, Right, Left, Right, B, A, Start for a surprise