I have heard and understand your concerns. However, I don't plan on it, for a number of reasons.
Spoiler warnings from here on out;
Firstly, the abstraction of the nature of suicide. By the time the nature of the deadly event is realized for what it is by the characters (that is to say, self-inflicted), it has been made clear that this may not have been as deadly or as permanent an event as real-world suicide truly is. In fact, to put a content warning for suicide alongside a game that makes abundantly clear that Kyle can "get better" would be to do disservice to its nature. Compare my Ludum Dare entry "Not Clowning Around" that has, what some may call similar subject matter, but I disagree. The "joke" in Not Clowning Around is that of an implied and genuinely permanent event, hence why I did place a content warning alongside Not Clowning Around, but not beside Animal Lover.
Secondly is the abstraction of the event. In stark contrast to, say, the suicide in Doki Doki Literature Club, the visuals do not immediately imply suicide. They do communicate a traumatic event, that is to say discovering the body of a beloved animal run over by a car, but this is not the same as placing my character's cloudy eyes on screen in order to shock or terrify. In fact, it was a point of discussion during development to make the visual unclear in terms of detail but deeply clear in terms of impact. A far-away visual of an animal's still body. These do not carry the connotation of suicide, and intentionally so. Granted, the subject does become suicide, which leads me to my next point:
Thirdly, it is not immediately clear that this tragic event was self-inflicted. It is only realized after a cascade of realizations surrounding Kyle's character that this could have only been self-inflicted, during the same conversation where the characters realize, due to the magical nature of the story, Kyle may manage to arise from the dead. The tragedy is, thus, not that Kyle is gone forever (as real world suicide exists) but that he was in such a deeply depressed state that he would act upon his suicidal tendencies. Realizing that someone is capable of suicide is a tragic, but wholly different circumstance than someone actually having committed suicide.
Fourth, as an extremely late-game event, in a story rife with references to and usage of sex, alcohol and violence, that even were the player unaware before that the story is mature in nature, they should be aware of the game's mature nature by this point. Either the children in the room have been shooed out or they're still playing when they absolutely shouldn't be.
Fifth, trigger warnings and content warnings have been shown through multiple studies, such as a study from Sanson, Strange and Garry (cited below) on the relative uselessness of trigger warnings, or a study by G. A. Boysen (also cited below) on how avoidance of triggers and trauma reminders may contribute to the persistence of PTSD. I just haven't been personally convinced that trigger warnings are particularly helpful.
But lastly, even if none of these things applied, which they all do, to add a trigger warning to a serious discussion of a character's mental health is something I find personally distasteful. This is a game intended for adults and while a discussion of tone is certainly feasible, (I feel as though it was a smooth transition from benign hardship to the existence of life and death in banal situations), some may not agree. Regardless of whether its execution was "good" or "bad", my intended audience consists of adults, and as an adult I would prefer if the storytellers giving me stories checked my ID and sent me on my way to the theater, rather than prefacing the story by telling me what events are going to occur in it on the off-chance that this story is too mature for me.
I understand your concerns, I do, I even empathize. But I feel it's a strange askance of a creator. God knows I'm not taking it personally, but I can certainly imagine others who could, or would, and I would have a hard time blaming them. I've marked Animal Lover as having sensitive content on Steam, Itch and Google Play.
If you would like to discuss further means by which to mark Animal Lover as being a game with mature content, I am naturally, even eagerly open to discussing it. However, trigger warnings and content warnings are not something I'm currently open to considering.
Regardless, I genuinely appreciate you guys reaching out with your concerns.
-Wilson T.
Boysen, G. A. (2017). Evidence-based answers to questions about trigger warnings for clinically-based distress: A review for teachers. Scholarship of Teaching and Learning in Psychology, 3(2), 163–177. https://doi.org/10.1037/stl0000084
Sanson, M., Strange, D., & Garry, M. (2019). Trigger Warnings Are Trivially Helpful at Reducing Negative Affect, Intrusive Thoughts, and Avoidance. Clinical Psychological Science, 7(4), 778–793. https://doi.org/10.1177/2167702619827018