What THEY have said?
The C64 was the last hacker's machine. You could get away with incredibly nasty programming tricks, and most of the time you had to! No computer has been so thoroughly explored as the C64.

By exploring the very limits of the machine's capabilities, coders performed feats that are simply incredible. Just look at some of the modern demos like World of Code 3 by Byterapers or Access Denied by Reflex

- You simply won't believe that it's all done on a machine with a 1 MHz 8-bit CPU!

End of quote. This bit was found on some ex-64 scener's website, and it's quite wonderful. Old workhorse, Commodore 64, has been a virtual backbone of demoscene for over a decade now. It's limits are still unfound, the demos get still better and better.
It's wonderful seeing how our old 1 MHz machine gives new Pentium a crappy price/performance ratio.

How is this done? Endless working on code, and instead relying on increasing CPU performance, optimizing code to get everything possible out of existing frame. This is very dominant on the Amiga-scene as well, and we've all seen how C-64/Amiga coders outperform existing PC-coders by digging into their code and making it more efficient. This is how it should be done.