Recent reviews by The Flappable Ms. Valentine!

Short version: if you liked Furi, and you have that hunger to master the challenges within it, get the DLC. It's an extra boss in a game about boss fights; the DLC won't change your mind if you felt iffy on the base game.

Good:
* The Flame is really good, combat-wise. Satisfying on Furi, surprising change-ups in Furier, a lot of nice variations within the different phases from the main game. Really enjoyable, and since this is basically the whole DLC, take it as a strong recommendation. But...

(Nitpicking ahoy)

Bad:
* All of the polish around The Flame is pretty lackluster. Not having an intro or closing cutscene really leaves me hanging for some personality. Like, he seems to have some in the facial animations and between-phase cutscenes, but it feels pretty sparse compared to the main cast and for a dude built on revengance, I really wanted more out of the non-fight stuff. I'm hoping that there's an insertion point for him in the main storyline with cutscenes and a smidge of context, but the DLC is accessible in the main menu from the start, so I'm not expecting this.
* More polish gripes: his theme is really lackluster, and also doesn't really contribute to giving him a personality like the themes for other stages do. Sorry, Scattle.
* The stage also gets very claustrophobic at certain points, which is cool, but also does feel a bit too tight for some of The Flame's attacks, especially on Furier. Truth is, though, I just need to git gud.

Like I said though, none of these complaints should deter you from getting this DLC if you enjoyed Furi. I paid four bucks and binged on it for three hours. I also know I'm gonna go back and put more time into it, because this game makes me want to play better for my own satisfaction. It's great. Buy it.

Oh yeah, and that extra content they're teasing on the store page? It's excellent, if you're prepared to struggle a lot. Really fun DLC on the whole.