Battle Royale III: Frenemy mine.

[Top cat]

Yes, but samus has always had superior equipment and stuff to her smarter enemies. When she decks huge creatures all the time, it's not just that she's that good (though she is), it's also because they're kinda stupid and have absolutely disgusting fighting technique. A real fighter like the swarmlord wouldn't just constantly lunge in melee and then take about 5 seconds to figure out that samus dodged. Remember fighting meta ridley in metroid prime? Just how much of a chance do you think you would have stood if he'd just kept slashing at you and driven you into a corner rather than used his idiot lunge attack?

Also, the swarmlord is an ~8m biped. It's probably pretty fast and has a psychic ranged attack.