Thank you for such a lengthy, meaningful response and engaging in the debate in a respectful way!
Apart from the dissonance I highlighted as the keynote, the mechanism of the game in relation to the point it *might* be trying to make is yet another issue, which I thought I'd better not dwell on too much, mostly because it's a simple, short game, the creator is a young, relatively unknown one and it's an artistic expression after all, so attempting to critique these technical aspects too harshly doesn't seem fair. We're facing shortage of creative expression and I stand for encouraging artistic value that is self-made and not stolen or mass-generated, regardless of my personal taste or its closeness to some kind of arbitrary perfection. The reason I wrote this review was to focus on the subject of artistic freedom, pertaining to the slippery slope of eradication of the taboo in art in the long run.
If I were to give something constructive on the executive side, though, it would be my observation how the game is designed to guide the user towards violence, which undoubtedly stands as its main/goal essence, ultimately leaving very little choice or flexibility for the player (I did want to go back to the "safe" tools, but once the next one is bought it's not possible to revert it, which I find a major drawback in case we're aiming for the "let's check the level of your empathy" effect) and causing the feeling of incompleteness in the route towards the good ending, like we're either missing out on or deliberately avoiding the main part it was all designed for. If the game facilitated non-violent paths better, the effect you're talking about would be more feasible. I just don't think that's the case at the moment.
You're actually touching a pretty underrated psychological niche with the dehumanization as protection. There's an undoubted biological mechanism behind human empathy increasing in direct proportion to the resemblance to our own species (which is why it also crossed my mind with the though that if the in-game art style was closer to realism, players would probably get much more reluctant even fully knowing nobody gets hurt for real). This particular field could've been an incredibly interesting area to explore, with the fourth wall breaking trope as a clever tool for stronger impact, if it was done in consequence to clear distinction between the player's immersive game-playing self and their actual values. TMI, but torturing even a simply drawn character wasn't exactly a fun ride for me as someone who somehow ends up feeling bad after accidentally stabbing a good guy in a first person RPG, but in order to figure out why we either enjoy or don't enjoy inflicting fictional pain onto anthropomorphized concepts, we need to enclose that within the fiction they belong to to begin with, because if we as much as assign real world human rights/emotions/violations etc. to the concept in question, the mechanism we're meant to ponder is left unclear, since the "it's not real, so why am I feeling this way?" puzzle becomes "it's not real, or maybe in some way it is?" instead. It's a gray area for the most susceptible ones.
You're right that fiction can absolutely impact you in countless ways on a cognitive and emotional level, which is why it's so enjoyable! To carry it on from there onto the territory of physical actions, there is the matter of consciousness and decisions we take responsibility for on the way, which is my conclusion of the whole point. It's a matter of who consumes the fiction more than what kind of fiction is consumed.
I haven't heard about the pet thing, but I just googled it and if you have a story to share, I'm honestly interested!