I'd be delighted to use V8... if I could figure out a way to get a deterministic estimate of the runtime of scripts (e.g. in languages that compile to a bytecod

I'd be delighted to use V8... if I could figure out a way to get a deterministic estimate of the runtime of scripts (e.g. in languages that compile to a bytecode I could add a "bytecodes executed counter" easily enough). I'm coding the game in Rust, but I really don't care what the language is coded in, linking in a language runtime isn't a problem.