Lightning Strikes posted...
So you haven't actually played the Primes then, which are also a closed plot arc, only tangentially related to the first three. Not adding to it at all.
The prime games are kind-of tacked on to the main arc, though. All of the sudden we find that it wasn't just SR388 and Zebes, there was also Talon IV which Samus visited multiple times in-between games from the original trilogy.
And ok, this would be fine if there weren't metroids on these planets. But there were--kind of destroying the believability of Metroid II being the "lets eliminate Metroids" plot arc, when space pirates apparently transported metroids to a bunch of extra planets, so Samus could not plausibly travel to just one planet in Metroid II and expect to wipe out all the metroids.
They're fine if you pretend it's a completely different or parallel universe, though. Then sure--those three are also a self-contained story.
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Cats land on their feet. Toast lands peanut butter side down. A cat with toast strapped to its back will hover above the ground in a state of quantum indecision