PICO-8 is a good competitive ground for performance coding: it's Lua, but with intentional limiters on size, performance, and source token counts. Writing good

PICO-8 is a good competitive ground for performance coding: it's Lua, but with intentional limiters on size, performance, and source token counts. Writing good PICO-8 code generally means code golfing, with the side effect of the performance limiters being designed to make small code also be fast code - so optimizations are often whole-program. Real-world performance on modern hardware is often a lot more dull and consists of finding the inner loops, parallelizing what you can, organizing the data to be cache friendly, then getting the loop fast at instruction level. You don't learn the same lessons from that because the majority of the codebase is "dark" and run too infrequently to show up as a bottleneck.