PG1995, although I have nothing to add to anyone that has posted previously, I think I can suggest a line of investigation that would drastically help point out what can be done when software is
truly optimized, just look up the
DemoScene.
Search YouTube for Demoscene, although you'll find some bad videos you will run across some absolutely incredible demos that have won at competition in the past, and if you look harder you can actually download many of the demo's that will truly blow your mind when run native.
Take a look at the code space restrictions and winners of some recent competitions, it will blow your mind as to what can be done given limited code space. Mind you it takes a lot of time and some real genius to do this much with this little.