Games that go for photo realism seem to bore me.

I generally can't stand "pixel art," which seems to me to be simply PR-speak spin doctoring which actually means "super ugly graphics that are deliberately made to look blocky & hideous for no good reason."

Oh, that reminds me, I kind of hate how Knights of the Chalice 2 will look compared to the style of its predecessor. Ironically, the first game used the here much maligned pixel graphic style, which I found kind of adorable despite the weird perspectives, while the new one has a much higher resolution but looks cheaper and less consistent in turn.

So I actually love good pixel art but games that don't commit to retro annoy me. If you make a game that looks retro but you've added modern skill trees/power-ups/whatever then please use the whole color palette and make detailed pixel art. You clearly are making a modern game with a retro feel. Unless you'll be giving me 3 continues, solid difficulty, and zero hand-holding I want sprites with more then 4 colors. I lived through the NES Era and I will play retro games or games with a retro style but have every aspect of your game commit to whatever you do. Unlockable characters, new game+, etc. are all fine but then don't let your art department phone it in by failing to provide any graphics older then 1987. Make them do 8-bit sprites and stages with more color or animation then an NES could have handled since you're doing more of a retro remix idea.

Exactly, it's immersion-killing, for me it worked against feeling immersed in a fantasy setting, takes you out of the illusion, made Warcraft 3 feel "fake" and hard to care about. It wasn't the only problem (didn't like aspects of the story and the gameplay either), but the cartoonish graphics (which were a negative contrast with previous Blizzard games, or something like the Age of empires games) really didn't appeal to me at all.
Also a reason why I'm not overly interested in the Divinity Original sin games, that style just looks terrible imo.

Any anime type art.

FTL Faster Than Light, I haven't played yet, I mean... I hear the game is really good and many people recommended to me but always there is a better offer for the same money and if I have to choose between one and other I always choose the other :/

Pixel Graphics that can't even be bothered to match the basic graphical fidelity of the NES/Famicom.

I'm not asking that you go to the level of detail seen in the latter NES games that had custom graphical mappers installed to allow parallax or scrolling backgrounds, I'm saying at the very least have graphics distinct enough of the Pulsewave/Black Box series of games. So you know, Gyromite or Vollyball.

Secondarily: Games whose graphical style is the equivalent of mIXed cAsE in terms of consistency.
Games that can't even be bothered to match their artstyle entirely to their main one give the feeling of finding chunks in milk. No matter what the situation, something clearly has gone wrong. Narita Boy just so happens to be a great example of this. The MC is some "Mister Pixel" character, while everything surrounding is a wildly varying scape of mixed graphics ranging from alien beast to massive detailed cityscapes.

Fifth: Since we're on a roll with this: Fake graphical flaws that serve no purpose except to imitate how crappy technology used to be.

I am tired of people pretending RF input was a good thing. Fake scanlines, tube bend, fuzzy film grain, chromatic aberration, signal ghosting/image doubles, vertical hold, and more. CRT monitors were pretty good at what they did. CRT televisions were awful. I don't see people waxing nostalgic for the passive matrix LCD screens, so why do people swoon over thumb sized scanlines, anyway?

Oh, and for a specific game, The Binning of Issac, full stop. It is everything that was wrong with Newgrounds as a platform rolled into a single massive ethos of misbegotten balance patches. It seems like a great game to experiment in, completely running aground of a completely unappealing artstyle.

I agree. There are few things worse than a game that doesn't have a consistent art style... or that looks like a patchwork quilt of library assets from vastly different projects.

Tumblr SJW style.

Why is everyone fat in that cat game?

Hiveswap has a unique style which happens to be remarkably ugly.

Candy Crush-style cartoon phone garbage.

WoW-style character designs, which I now associate with phone garbage (I liked it back in the oughts).

Anime fantasy clothes are often very ugly (always hated it, even before the phone garbage infestation), especially women's (and children's) clothes which look like underwear but aren't. Also, cargo shorts. Give me a true and honest barbarian babe in a bra and loincloth.

Early 3d and its imitations (e.g. Anodyne 2, although it's not the only reason to avoid that game - the artist is a sex offender). I love clean, semi-abstract modern 3d, though.

Fake pixel art: scaling pixelized sprites by increasing pixel size, rotating pixelized sprites by drawing pixels at an angle, sliding the sprite in high-res, just plain filtering higher-res images and stock effects as pixels because ohmygawd so retro!!!11!.

Shitty fonts. Localizations of Japanese games in particular suffer from it, but if a Western game has a shitty font, it's a good sign it's garbage. Gentium is free, use it.

Can't Agree more!

Borderlands series

Yeah they remind me of THIS!

Cell Shading? Yeah frigging tell me about it!

Have nothing against Cell Shading, some games nailed it, Okami, Zelda, XIII they all look good. But I can't stand Borderlands art style. I am very happy that Gearbox sold millions of copies of Borderland games but it's not for me, too bad it didn't helped them and they lost their independence at the end. But maybe it's a good sign for new Duke Nukem games, who knows.