No worries. You were very specific in your request for feedback, so I wanted to be sure to give it a look.
So you're at a clearly higher level than what I'm used to giving feedback on. So what I'm recommending, even if I don't always coat it in flowery language, is all more advanced stuff that mean that you are progressing really well in your writing.
First issue is paragraph and sentence construction. Again, it's wonderful to see someone who is comfortable writing paragraphs more than a sentence long. But, in a fight scene, you have the extra afforded room to play with your paragraphs and sentences so that the rhythm of the prose matches the tension in the scene. I'll edit an example below for you to see.
The novae kept a stranded eye watching the tree, while she herself quietly slipped off the roof, ensuring her path would never cross the killer's line of sight. Reaching into her own coat pocket, she withdrew a flintlock pistol, took a deep breath, then made her approach. Being completely silent was impossible even for her, but she had another idea in mind. Letting one of her strands of eyes creep its way towards a bush in a different direction, she lightly shook it in the way some small animal might have. It definitely caught the killer's attention, making them tense up warily, but it was enough to mask her footsteps until she was just below them. She stopped, taking a deep breath in.
"The novae kept a stranded eye watching the tree, while she herself quietly slipped off the roof. Her path would never cross the killer's line of sight. Reaching into her own coat pocket, she withdrew a flintlock pistol. She took a deep breath ... then made her approach.
Complete silence was impossible even for her, but she had another idea in mind.
Letting one of her eyes creep its way towards a bush in a different direction, she lightly shook it like a lure. It was enough to mask her footsteps until she was just below them.
She stopped, taking a deep breath in."
Here, I've cut some verb tenses that were making the pace much slower. I group actions into smaller paragraphs as long as they are direct sequences of events. And I've created a few one-line paragraphs to draw emphasis to changes in pace. Again, this is a stalking/hunting/survival scene. Her mind should be choppy. Thus, the prose can be choppy. And that heightens the tension when done in a controlled way. My elipses are somewhat controversial (along with m-dashes which people now think is the exclusive right of AI nowadays). You don't have to use them. But, again, you get more license for weirdness in your storytelling tools when covering unusual ground in your story.
You don't need all caps in mature writing. Let the dialogue itself carry the urgency. Instead of:
"STOP WHERE YOU ARE! Stay down! Put your hands up, or I'll shoot!"
Do more with less like:
"Don't. Fucking. Move."
Three words, a small amount of unusual punctuation, and yet it carries weight, tension. For tension, less is usually more. Of course, you may not want hardened killer tone. You may want nervousness or something like that. Which can all be achieved in much the same way. The same goes with using a bold font later. Save bold font for computers speaking, or something like that. Let your dialogue itself hold the emotion and urgency.
Next, all of your dialogue is just a little ... stereotypical bad guy. Which is also robbing the scene of some power, bringing it back to the mundane. Even if these are the only lines the killer ever gives, you'll heighten the tension by actually making them seem like a distinct person.
Save sound effects for when you want to write the screenplay of the next Adam West Batman. Bop! Pow! Zing!
"...I never said I was bluffing. Stand down! Don't make this worse for yourself." There was an aggression in Kurai's voice that left it unfamiliar even to herself. The shaking in her voice had gone away.
Again, losing tension because your characters are saying too much, and yet nothing at all.
"...Ahh... aagh... ghhh... gaahhh..."
More silly sound effects, also undercutting tension.
With another roar, the assassin once again launched herself forwards, igniting her fists with explosive potential. The first blow landed on Kurai's forearm, eliciting a gasp of pain as the flames seared into her. The assassin was only somewhat strong for a human, but her fires were beyond reproach. Every single burst of flame was like the roar of a dragon. They were a force multiplier onto every strike.
You're describing the attacks, but not the consequences. Remember, a single punch to the throat that results in something cracking, the target gasping for breath, choking up blood, is more powerful on the page than any 12-step combo with flames and fire. I'm not saying you can't make your choreography cool. You absolutely can. But you need to show the consequences of a strike for it to matter. Also, less continues to be more. The longer a fight goes, the more it starts to drone on for the reader.
(Skipping a lot of the same sorts of problems I've already mentioned.)
It completely tore through the novae's stomach, along with her liver, intestines, lungs, spine, heart, and many, many other parts. Yet, it wasn't powerful enough a blast to reach her skull. It was something she could still recover from. All of her viscera could still be reabsorbed. But gods above, it was painful. Her vacuum field ended in an instant; she had no concentration left to use on it. But mercifully, somehow, it wasn't needed anymore. The assassin finally, finally lost consciousness. The shock of her arm being blown up must have been enough on top of everything else.
Here, you are undercutting the pain. You are telling the reader that the explosion hurt, but not showing it. The burning like molten lava being dripped in ones bowels. The searing, white-hot pain that blurred her vision. You get the point. Show us how much pain your protagonist is in, don't just tell us.
Now for your questions:
1.) How is the pacing overall? Too fast, too slow, inconsistent, etc.
Headed in the right direction, but needs work.
2.) How weighty do the attacks feel? Do they portray a lot of impact, or do they feel toothless?
They feel a bit toothless, simply because you need to do more to show the consequences of the attacks instead of a large amount of cool attacks.
3.) How coherent is the action? Did you ever lose track of what was going on, or could you picture the fight well enough throughout?
It's pretty coherent. You just need to take a little bit more time adjusting for your protagonist having non-human anatomy.
4.) Did the fight end too quickly, or did it feel like it lasted long enough to sell the scene?
If anything, it went on a bit too long. As a reader, I would prefer a briefer but more dynamic fight.
5.) Should there be more background effects going on? Describing panic from any observers, possible police sirens in the distance, the way fire (inconsequentially) singes background objects, other environmental details not part of the fight itself.
Yes, but sparingly. Mostly, I want to see the effects of the attacks themselves. A little background detail would be good, sprinkled here or there. But not a whole condensed paragraph, unless you are using observation to explore the psychology of the characters.
I hope that helps, best of luck!
