It took significantly more missiles than 100 to do it the hard way if I recall, too. I distinctly recall counting my misses because it took pretty close to as many as I had. I don’t, however, recall my completion percentage. Quick sloppy research says 150, which I’d imagine means 160, keeping with the whole 5*2^x thing it has going. Not fun at all, that.

And you know, to this day the whole “life cycle” angle still bothers me. Particularly in light of how most sequels had the good sense to avoid ever acknowledging it again.

Hatchlings don’t appear on the metroid-o-scope because they haven’t matured. The sudden jump in metroid numbers in the final stretch is because eight hatchling matured to larval metroids. Given the way so many metroids change form once Samus draws near, we can assume metroids have the ability to molt into a new form at will to deal with a threat. Hooray, I just explained something that really didn’t need explanation.