Even with Javascript, there should only be a 10x performance penalty at worst, and getting to 2x penalty is feasible.

We do need to scale based on screen size though - copying pixels around is expensive.

But a low-end machine from 10 years ago should be mandated for all developers.

If you can't get a simple game like that perform well even when written in JavaScript on a semi-modern PC you wouldn't be able to do it in any language. It's certainly not the issue.

PC was ridiculed for its bad graphics capabilities by fans of other home computers. Only over time PC's capabilities for graphics and video games improved piece by piece until after many years PC fans had the last laugh.