This may come off as faint praise, but planning a route through a level to minimize the number of tag barrel visits is a lot of fun.

Fungi Forest, for example, can be completed in just 6 tags by starting with Tiny, then switching to Chunky > Lanky > Diddy > Tiny again > DK. It helps that I can explore the levels with my mind's eye so nothing escapes me.

When you know where everything is off by heart, DK64 becomes a zen experience where I can let my mind wander and bask in the joy of collecting.