Copy paste from pacman boards.
I'd say it's easy for Samus and I agree with KayJay, but I don't even think it's even. We can easily close gaps with Z-air to get within close proximity. Our damage output is generally twice as high because of our combo ability and potential for followups off of our normals.
Before Pacman will have gotten his key, we'll probably already have a charge shot and be running towards him to apply pressure. Pacman gets outranged pretty hard even without the use of projectiles and I'm positive that charge shot eats the key. Hydrant is also the only projectiles in the game that charge shot loses to, but with little to no consequences.
Pacman gets juggled easily by Samus, but he cannot juggle us. Samus catches his landings pretty easily. The hydrant actually makes it easier, but the character seems to have a hard time catching our landings without his key. I would say we actually go even in terms of frame data . Don't forget that we have a 3 frame jab, 5 frame multi-hit up-air, 6 frame disjointed d-tilt, but we must acknowledge your 3 frame n-air. It's a hassle when we attempt shield crossups with up-air.
Finally, Pacman can't kill Samus, but we have an easy time killing him. We have a b-air that kills most characters from the center near 110 and a b-air trump that kills middle weight characters in the 70s. Samus has a spike, an amazing edgeguard tool in the form of u-tilt that kills on ledge near 80, a charge projectile that kills when half charged off-stage and somewhere in the 100s from the center. We have guaranteed killsetups into f-smash against your character because of his floatiness. Airdodge reads against Pacman near the ceiling come pretty easy because we can challenge hydrant, thus he gets killed off the top with Screw Attack just like any other character.
What does Pacman have against Samus? His key, fruits, and smashes, but his smash attacks are like frame 18. Samus is a heavy weight, floaty, and has above average recovery. You will struggle to kill us, we dish out more damage, and kill earlier. This matchup is absolutely terrible for Pacman.
I think we win 60/40.
ez monies.