What are the most instructive Zurich 1953 games? I'm a club player that never really figured out the importance of studying master games. Since I want to improve my middlegame understanding I read that Bronstein's Zurich 1953 is an excellent place to start. However, going through the games takes 1-2 hours/each and I was wondering if some games illustrate the key concepts better than the other.
There are of course classics like the Averbakh-Kotov game. 

But generally you get out of chess study, what you put into chess study. So you should play through games that interest and fascinate you. It should be fun, not something were you try to minimise the time spent from the outset. 

For me, that meant for a long time wild tactical games. I played for example through the games in Bronstein's "Sorcerer's Apprentice", Tal's "My Life and Games", Christiansen's "Storming the Barricades" and Aagaard's "Attacking Manual". 

I do own Zürich '53, but I don't think I ever spent much time on it. 

But if you already own the book and want to proceed, I would recommend restricting yourself to well annotated, decisive games that feature openings from your repertoire.