As much as I dislike most of the Flower-Humans, I think Flowery would've killed it with some more development time. I liked that Ralsei had someone to butt heads with, both because him and Flowery are "not-quite-Asriels", and because he 100% knew this was coming due to the prophecy. He knew Asgore was going to bring his perfect flower man to life, and he knew it'd be a colossal pain in the ass to convince him to move the story along.
It's not like Flowery's motivations were completely wrong, either -- these were our first Darkners that were still living things in the Light World, so they existed in a weird limbo-like state where they're alive but motionless in the Light World and one-note caricatures that Asgore had applied to them in the Dark World. It could've been an interesting perspective to throw at the player, had it not been mentioned that the Flowers couldn't come to Castle Town because their Light World counterparts require constant maintenance, which... makes no sense, because their forms completely change when steeped in darkness, just like everything else...
Also having 7 of these unique beings introduced and fleshed out in the same chapter was a Herculean task that was never going to work, and it's kind of annoying that Flowery suffered the most for it. I'm not even considering the fucking mouse as a character, and the chef's an obstacle at best.
The OST doesn't have very many hits this time around, but I'm getting a little bit tired of the leimotifs. I get it, it's the Undertale chapter. It's all about Undertale. There's flowers and Asgore is relevant and woo it's Mad Mew Mew from Undertale!! I'll at least give Flower Man (Flowery's boss theme) some points, because it's supposed to be cheesy, and the drop syncs up really well with a lot of moments in the fight.