Try Crush
This is the real Crush compiler and VM, compiled to WebAssembly. Nothing is sent to a server. Programs here hold no capabilities beyond printing: no files, no network, no polyglot blocks. Asking for one is refused, and the page shows you why. That refusal is the point of the language.
What runs here
Crush source is parsed, compiled to CASM bytecode and executed on the portable CVM interpreter, the same pipeline crush-run uses natively. Each run starts fresh and is capped at one million VM instructions.
What doesn't, yet
Polyglot blocks (@python, @javascript, @bash) need a host process, so the browser refuses them. Capabilities such as fs and net are not granted. Green threads (spawn) don't compile in the browser build yet. Programs that read input with io.read pause and ask you for each line.
Run it natively
The toolchain is open source at nixpt/crush-ast. The language guide lives at docs.crushlang.org.