What they had done was wiring kernel level operations, without any of the userspace security checks into the wasmer. Their logic was that given the sandbox of wasmer; what would happen if you removed the sandbox of the OS? And I remember their article was featured in HN for two days or so as well. It was interesting. It wasn't that WASM ran faster than C, it was the API calls. And I keep wondering about an architecture where you have a highly sandboxed universal assembly with some API hardening; a middle ground, and so imagine an app that ran everywhere and was 10~100 times faster. Could be really cool.