Wow, wasn't expecting to even see a scoreboard for this here. Posting stuff from Calice Cup. It's a lot of fun to play, hadn't had the opportunity to try it before, but I'm a huge fan of Wild Guns and that sort of game. I was apparently the only person to 1CC this during it, though teammate Jakazam also posted a solid score that ended at the final boss and I think a few other people made it there but not quite at the clear.
All the characters are functionally identical as far as I can tell. The ones with smaller sprites are a bit better for visibility perhaps, but
Roadblock has spicy MR BODY MASSAGE MACHINE memes going for him, so I used him.
It's surprisingly forgiving since there's tons of health items in this even if you screw up. However good luck 1CCing it if you can't no-miss to the final boss. Getting there really isn't too difficult to learn to do reliably and consistently until you reach Destro who is a huge asshole of a boss where he has tons of giant attacks, sends speedboats to ram you, and has massive and difficult to dodge sweeps that really demand missiles to cancel them on his final phase. I had a bunch of trouble until I realized that on his last and most difficult phase, you can damage him directly instead of the hovercraft to stagger him, and you can get a feel for the stagger timing on him to interrupt him just as he starts doing the ultra dangerous sweep.
The last stage isn't too bad, though it feels like it takes forever to get a rapid item back if you got hit during Destro (and you probably did). Cobra Commander himself is extremely difficult and I find a bit of luck is involved in hoping some of his attacks don't hit you since they're massive. The electric beams are super fast, and his flame wave seems very hard to misdirect reliably. Quick killing his orbs is very useful for the first phase in stopping the electric beams, whereas the last phase seems to follow a learnable pattern, and you can cancel the dangerous grenades he tosses if you have trouble dodging them. He also can be staggered there which helps if it happens right as he starts an attack as it interrupts that one and forces him to use the next.
Japanese Version
BareKnuckleRoo - 2787 - ALL - 1P/Roadblock - ShmupMAME 4.2, no autofire as per tourney rules (my poor finger though, went through most of the Destro fight, final stage, and final boss without a rapid item)
(the reason it shows 2nd place in the screenshot is because I had a run where I gameovered at final boss prior, and popped in a credit to finish him off, which apparently doesn't reset the score, so credit feeding can apparently score higher than a 1cc, go figure)