Mate, take a deep breath - things are going to be ok. It's totally fine to not like a change in art style, and you are perfectly entitled to express that opinion and to no longer want to play the game.
But calling an update to the visual style of a game a "backstabbing" and celebrating "being a pain in [the developer's] ass" is taking things too far. Contrary to what you claim in your post, you are the one who needs to address the issue like an adult.
You are not the only person in existence to disagree with a change in direction for the development of a game. That happens all the time, and it's never as personal as you are taking it. Ultimately, the game belongs to the developer, and they are going to execute their vision for the game to the best of their abilities - you aren't entitled to keep things a certain way just because you previously supported the project.
Of course it's unfortunate when this happens - it's never fun to see changes to a project that you don't agree with - but this level of outrage is unwarranted and off-putting. You've obviously made your opinion known, so now just stop interacting with this project entirely. Stop harassing the developer and stop leaving rants on the comment pages. Try to forget about the project entirely - I promise you'll be less stressed if you do.
To Keo, I'm honestly pretty ambivalent about the sprite updates, but I do hope that you don't let people like the one I'm responding to get to you.