I don't think you understand how big the arms were, though
You're miles above the surface, on a platform suspended under a blimp. Falling means certain death.
Your foe appears before you, intent on killing you. And he will, if you aren't better than he is.
You're the only one who can stop him. If you fail, if you die, there is nothing left to stop him from accomplishing his goal of harnessing the most powerful source of energy in the world and using it to conquer and enslave everything there is.
You are a small blue animal man. Your powers are running very fast and slamming your back into things to damage them.
Your foe is an obese middle-aged man with a large mustache. He is Dr. Robotnik, and he is about to take everything from you.
You are Sonic the Hedgehog, and Dr. Robotnik rises before in his little round flying ship, only to immediately drop back down and rise again. His ship, barely big enough to contain his mass, now has a giant pair of arms, easily four times as long as you are tall, and is covered in spikes.
You don't hesitate.
Nobody has ever told you how silly this all is. It has never struck you that this is anything other than exactly as cool as it feels right now.
Nothing about this feels absurd to you. It is deadly serious. Robotnik's machine is called Big Arms, but you don't know that, and even if you did, you wouldn't think that was funny or strange.
You would think that makes sense. It has very big arms. And spikes.
You have not been irony poisoned yet.
You run at the machine, but it grabs you in the giant hands at the ends of its big arms and slams you into the platform on which you fight. It does not throw you off of the platform to your death. That would be unfair. The collision with the platform doesn't kill you, either. That would also be unfair.
Your rings go flying. You scramble to collect as many as you can.
More than one, you know, means that you are ready for action. You will not die as long as you have even a single ring. And so, you don't.
You try to jump over the big arms of Big Arms, but you collide with the spikes on top of the machine, instead. Your rings go flying again, and you scramble once more to collect what few you can.
The trick is that there is no trick. You have to be careful with your jumps. You have to dodge and run and avoid touching anything but the unprotected portion of Big Arms.
You don't wonder why there is an unprotected part. You don't wonder why Robotnik doesn't fly thirty feet away from the platform and spray bullets, or lasers, or napalm at you.
You don't wonder about Robotnik's plans. About why he's here in the machine at all. About why he doesn't send his entire army after you at once. Why all his robots have been so easily destroyed by a little blue hedgehog who runs fast and slams his spiny back into them. About why he chooses to power his robots with small animals. About why nobody else is helping you. Why there are no soldiers from any nation in the world willing to chip in and offer you support.
You don't wonder about a lot of things.
It takes you a few tries, but you eventually slam your spiny blue body into the vulnerable parts of Big Arms enough to destroy it. Robotnik's machine explodes around him, singing the fat man's face. He flees. The craft which supports the platform on which you have been fighting is broken, and your platform falls.
But you've done it. You've won. You fought the man in the machine and you beat him, and that means that you have, for the moment, at least, saved the world.
You know this to be true. You ran and you jumped and you fought your way here, and you fought Robotnik half a dozen times, and this latest victory is just one more to you.
You, Sonic the Hedgehog, the little blue animal man, have defeated Dr. Robotnik, the fat man in the flying machine.
You're a winner, and you got here all by yourself, by practicing and getting better at a game designed to give you ways to win if you just practice and get better at it. Robotnik was never meant to stop you, not really, but you don't know that, and you don't care, and he couldn't stop you, and he didn't.
You feel amazing. You're the coolest. You're the strongest. You're the best.
And why shouldn't you feel that way?