Comics were an erratic thing in my youth, a time before comic shops were a known thing to me or my parents (or they kept that knowledge from me). Buying more than two issues of any title in its proper sequence was almost unheard of.
The first issue of Crisis on Infinite Earths I actually bought was issue #12. The last issue.
I remember seeing and reading through the iconic "Death of Supergirl" issue in the stands, but it was too much for me at the time.
Marv Wolfman's purple prose aside, George Perez's page of the Anti-Monitor's shadow demons being unleashed on the earth was a horrifying image. Matched only by the last page with an institutionalized Psycho Pirate rambling to us readers with his final say on the story.
The whole issue was insane. I had very little idea of what happened before, but it didn't matter. I read this issue over and over again. I was finally able to track down affordable back issues of this series over a decade later--not too long before they finally came out with a collection.
How does the latest Crisis, the official "sequel," measure up? I might just tell you later.