Mario has a few advantages here:
- Intelligence. This should be a no-brainer. Especially with the homefield advantage, Mario could figure out a way to immobilize Shin. (Unlikely, though)
- Durability. Scales to 2.05 tons, allowing Mario to handle quite a lot of damage.
- Smaller Size + Acrobatics. He ain't no normal human, considering how absurdly athletic he is, so he shouldn't have any issue outmaneuvering the cumbersome movements of Shin.
- Likely better stamina. He spent over a day repeatedly attempting an unforgiving training course without rest. Couple this with his durability and he can stay in the game for a while.
- Power-Ups. The mini-mushroom would probably be more of a detriment here, but not so much with the others as they'd put Mario's AP above Shin's. Super Mushroom basically makes Mario stronger. The Super Bell would be Mario's best option here if he resorted to these, as it grants him greater power and the lithe movements of a feline.
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Despite the advantages Mario has, I'm not seeing too much of what he can do here. Shin's saving graces are his RE and Regen, practically nullifying most of what Mario can do since he doesn't have any insta-win options.
But Shin's odds aren't any better, to be frank. They're a lumbering sandbag that acts on instinct. Mario could literally run circles around them and wail on them all day because Shin wouldn't even be able to land a few decent hits (Throw in the Super Bell and it'll be nigh-impossible). The plumber even has that 'not-a-quitter' mindset, so he isn't giving up any time soon.
So really, Mario just.. outlasts if anything, or leads Shin someplace else where it ends up trapped/secluded/whatever. If hitting them ain't gonna work, that'd be his best bet.
what a weird match