I'm glad to get a continuation of this!
Just a little nitpick about the information at the start: I don't care much about this kind of thing, but I think "insinuated Fry/Leela" is wrong. I mean, you refer to them as boyfriend and girlfriend a couple of times. That's about as explicit as it gets. You'll probably want to change that for the finalised version.
A bit opaque if you haven't seen the "Evil Dead" films, but not insurmountably so.
The writing is still good, clear and succinct. Nothing but praise there.
Leela flung herself around, finger on the trigger, eyes on the snarling form
I think that typo speaks for itself.
prying loose the air duct covering.
It's a nice description, but "prying loose" doesn't really flow for me. I'd change to something like "prying away at the air duct covering", since to "pry something loose" is a very definite, brief action, and what the thing is doing seems to take longer than that.
Typo: "one of the creatures wings" is missing an apostrophe.
This disrupted its flight pattern with an outraged screech.
Another great description, but "with an outraged screech" should refer to the subject. Maybe expand to something like "This disrupted its flight pattern, and it swooped with an outraged screech".
“GET DOWN FRY!” She called,
"she" shouldn't be capitalised.
You capitalise "jar" at one point. Kind of funny, but I've no idea whether it's intentional.
have any more trick in that fancy little belt,
Should that be "tricks"?
he smirked lazily
"Lazily" can probably go. Or not, it's not that bad.
“but that doesn’t matter now. What does matter is getting out of this store in one piece.”
That's a bit of a cliché line, though I guess cliché is more permissible in dialogue.
She looked him dead in the eyes.
Stealth joke! I love her following line, too.
That was when Fry suddenly distracted them both by gasping
This can definitely be slimmed down. "That was when Fry distracted them both by gasping", or even "Fry distracted them both by gasping" would be preferable.
advancing menacingly on Leela…
OK, "menacingly" can definitely go. We don't think it wants a hug.
A bit of a too cheesy cliffhanger, but then, I don't know whether you'll keep the chapter divisions in the finished fic.
Not a lot to say about this bit. It's still just an action scene, but it's all well written, with nice interactions between the cast. While the cliffhanger may be a bit over-the-top, I obviously want to know what happens next.