Unless we do something about it, you will not be able to see Rust panic messages when running in a web browser. This means that, if your game crashes, you will not know why.
To fix this, we can set up a panic hook that will cause the messages to appear in the browser console, using the console_error_panic_hook crate.
Add the crate to your dependencies in
[dependencies] console_error_panic_hook = "0.1"
At the start of your main function, before doing anything else, add this:
// When building for WASM, print panics to the browser console #[cfg(target_arch = "wasm32")] console_error_panic_hook::set_once();