I would say that you should have a good toolbox of simple practical techniques that you understand at the level that you can re-implement and combine at will. Because that's what I would love to see in a candidate, speaking as a ten-year game programming veteran.
It's also a good way to look at interviews. Some people would try to use a programming interview as a place to demonstrate the most advanced, novel or little-known cool thing they know. But even in a specialized position, interviews are largely explorations of breadth, not depth. If you want to show off your depth, write a paper, blog post or library with a demo.
"When someone throws you a tough interview question, be sure to keep attacking the problem as vigorously as you can"
I've seen people give up on tough interview questions and I wonder if they realize it's simulated software combat - how they reaaaact - not the answer that is important..
It's also a good way to look at interviews. Some people would try to use a programming interview as a place to demonstrate the most advanced, novel or little-known cool thing they know. But even in a specialized position, interviews are largely explorations of breadth, not depth. If you want to show off your depth, write a paper, blog post or library with a demo.