I'm a little confused by this. By "storefront", do you mean the front of the store, or a front for the Foundation?
"Storefront" is vernacular I grew up with that means the a building that houses a store, or is designed to house one. I wanted things to be a little bit slang-y in the story, but I'll keep an eye on this and others for possible changes for comprehension.
"Yep" is a bit out of place, and doesn't read right. Consider removing it.
Same thing with "yep". Wanted it in to show the speaker slipping out of formality, but I can probably find something similar that sounds better. Will pick at this one.
"Stupid" is repeated too much, and "other hand" should be changed to "the other".
Agreed on "the other", but "stupid", I'm not sure what to do about.
I wanted that repetition to be aimed at his partner to imply the speaker's disapproval of what the partner did, while deliberately trying not to make the speaker's language of disapproval not be regretful (I felt like any wording that easily implied regret would tip off the fact that something bad is going to happen to the partner in connection with the giraffe too quickly).
The "stupidly", then "stupid" close repetition is a little janky, though. Hm.
"Spider webs" shouldn't have an s after it, due to the fact that the spewing stuff is singular. This might be a bit nitpicky, but "moved like something alive." could be rephrased as "flowing as though it were alive" to remove the repetition of "like".
I like where you are grammatically, but this bit I want to keep because it isn't grammatical. I'm still not sure of how to slip in other quick instances of the speaker switching from formal tone to vernacular, but this one has just the right timing and amount of slang I want him to slip into before "correcting" the slang again.
How could his partner shoot the narrator point blank when they're incapacitated? Is this part of the anomaly?
No, not part of the anomaly (and no, no established scips or characters were included); I completely missed that I'd implied the partner had been completely incapacitated. Will stare at this until I know how to fix.
I agree with all of the other grammatical changes you offered, and thank you muchly for the kind words too. A-revising we will go!
EDIT: Version 3 is live. Does it tell you more about what's going on? I'm still trying to let the reader figure it all out for themselves, and I'm happy to say your first explanation (of version 1) is pretty close to what's really going on.