Bro, how???
This is Luffy going all out.
Island scale attacks.
Both Luffy & Kizaru haven't gone all out yet, they've just stalled each other so far.
That would be absolutely useless on Kizaru.
Luffy is doing the best he can here. All out means he's using everything he has in his arsenal, and everything that can be effective against Kizaru.
He's used so far
G4 Snakeman + FS (to try and deal with his speed)
G5 + increased mass + advCoC + adCoA and this attack even has flames on it, might be indicating speed or some shit like red hawk.
You're never gonna see Bajrang Gun because Kizaru will make a fool of him if he used it.
Meanwhile Kizaru legit looks like he hasn't
really even started. I'm disappointed with how Kizaru looks after taking that punch, even as a Kizaru fan, that's silly. He's not supposed to be even close to the tank Kaidou is, I made myself believe other top tiers would be near deaths door if they took such advCoC hits to the head, but Kizaru is making it look better than a base Luffy punch on Kaidou.