To back up the "surprisingly efficient way to get a speed-up" thing: I once wrote a toy compiler, without an optimizer and without even a register allocator (so all variables lived in stack memory). In my test benchmarks it was roughly 4x slower than Clang at -O3, IIRC.

That's not exactly blazing fast for a low level C-like language, but it's not bad. It's infinitely faster than what I've ever gotten a toy interpreter to be.