The old one was totally out of date (it mentioned typed arrays and a
specific set of browser versions against which the previous Emscripten
build had been tested).
Also, a couple of users in the last day or two have reported
mysterious failures of the WASM puzzles, which I haven't been able to
reproduce in the same version of the same browser. So something odd is
going on, and this seems like a good place to put suggestions about
what diagnostic information to send.