Yeah I wrote my comment initially thinking it was just rolldown being used, so the "rust-powered" was confusing, I think the tagline is actually ok now that I know this, but really you're doing two things here

1/ an alternative framework for RSCs similar to nextjs, tanstack or react router

2/ a rust runtime for javascript, similar to node, deno or bun (except maybe not as general purpose)

Exactly! Those are the two main layers.

The runtime piece is definitely less general-purpose than Node/Deno/Bun. It's optimized specifically for React Server Components with things like streaming, Suspense boundary handling, and server action execution baked in. You wouldn't use it to run arbitrary JS apps.