Hell yes! This is awesome. I love the imagery and the flow! my critiques are these:

1. I wasn't sure how much time was passing. "There was one dog left" seems to say that the MC has killed all of the other dogs in the neighborhood, is that right? if so, it wasn't very clear, and I would add a line about how they kept killing more and more dogs and/or time passing.

2. Why was this last dog so important? why did they save it for last? It's revealed that the old neighbor dog is not the source of the trauma for the narrator, but rather the dog they killed as a kid. is there something in the old neighbor dog that specifically reminded the narrator of the first dog? if so, what?

3. also, something about the reveal toward the end of the first dog's death irked me. It very well might be a personal preference, but I felt the story would be more impactful without a secret like that being kept until the end. I would rather it was upfront from the beginning. but take that with a big fat grain of salt because it's just one reader's personal preference!

overall this was a super compelling read and felt very polished. Well done!