idk what happened to Nova so I'll do this instead.
Gear Fourth is still based as hell, but apparently the drawback is some sort of time limit - given that Luffy had only been in it for about a minute before he was all "ruh roh running out of time", that does seem pretty severe, especially when you consider that the other two forms could be kept active for as long as Luffy wanted but with consequences. I imagine there's some severe consequence for going over the time limit, but that'll probably be next chapter if anything.
Oh, and according to Law, you can use too much Haki at once, whatever that means. Does Oda mean to put a cap on spirit in One Piece? MADNESS.
Surprisingly, Doflamingo is the one to remind us of the concept of Awakened Devil Fruits - and apparently, they go beyond simple Zoans. He's turning the city into his weapon, which is both OP and pretty legit. How he's still standing at this point is beyond me.
Riku's still Jesus at heart and wants everyone to survive, yeah yeah. I won't deny that it made me feel warm and fuzzy inside nonetheless.
And now Luffy is a Bullet Bill (can't tell if "Fly!" is a command or an attack name, since there's no Gomu Gomu before it) and has embedded Doflamingo into the mountainside,
likely definitely defeating him regardless of what certain users may think. Looks like it's over folks, time to watch the cleanup.