Art styles

For Capcom, you can see various "generations" of artistic styling on their fighting games, i.e. mostly Street Fighter.

1. Street Fighter I was made in 1987 on very primitive hardware by the standards of what was to come. The art looked really good for the year that it came out, but it looks primitive by 90s standards, with stiff, non-fluid animation and relatively little detail.
2. Street Fighter II was the same style as the earlier game, but the hardware was improved, and everything looked better. The character animation was both more fluid and more detailed, the backgrounds had a great deal more detail and animation, etc.
3. The Street Fighter Alpha games used the same style as both the Marvel and Darkstalkers game, and looked less like a video game and more like an animated movie, by design. The hardware was improved (CPS1 to CPS2 board). Everything was again improved; the backgrounds look wonderful, the characters look pretty good, although they're still the same size/resolution as the earlier style--but artistically they were very different. I'm not 100% sure that the frame rate or fluidity increased. The F/X stuff looked tons better too. This artistic style actually carried forward for quite some time, and overlapped with the next generation of art.
4. The Street Fighter III games were on improved hardware, the CPS3 boards. There were some graphical improvements associated with this, including a greatly increased framerate. The 2-D backgrounds from this era look really good; some of the best ever made, in fact, to this point. The size and resolution of the characters still look the same, although the art style was revised. It's still animated movie-like, however. The vs games were also on this same hardware, although they usually used Alpha-generation sprites, or newly drawn Marvel/SNK sprites that were the same style, more or less. This is also where some 3-D backgrounds started to pop up in the latest versions of the Marvel vs and the vs SNK games, although they do not, in my opinion, look as good as the 2-D backgrounds of the same era.
5. Although chronologically out of order, I think this belongs here; the high resolution UDON drawn sprites and backgrounds of the Turbo HD Remix and the Switch-released Ultra Street Fighter II game. This stuff looks absolutely FANTASTIC. I actually think I prefer this style of art to any that I've otherwise seen, although some other franchises have very similar style art.
6. Street Fighter IV is the first 3D Street Fighter game (I'm obviously not counting the EX games) although that's just the graphics, not the gameplay, which remains solidly 2D regular "Street Fighter-like." I think this game looks fantastic, mostly, but I admit to preferring the animated 2D style of generation 5. The only thing that makes this better than 2D is the ability to have alternate costumes as 3D modules.
7. Moving from the PS3 (and Xbox 360) to the PS4 allowed for higher quality 3D animation, but the reality is that Street Fighter V doesn't actually (necessarily) look better than Street Fighter IV. The art style is often more caricaturized, there are really bad clipping issues (especially in the story mode cut scenes) and a number of characters have really badly designed new looks. 

In general, I'd say that of the Capcom art style generations, I like the Alpha stuff quite a bit, although I also admit that it looks dated now. I also like the SFIV 3D models, but the UDON high quality 2D animation is my favorite Street Fighter art style. 

Because I've started talking a bit about the beat em up tangent to fighting games, its worth pointing out that beat em ups at Capcom never really advanced out of the SF2 style regardless of what hardware they were on. Maybe Captain Commando has a bit more of an Alpha feel, but I don't think so. That said, a number of beat em up (and other) Capcom characters were remade in different styles because of crossover games, including loads of Final Fight characters that came to Street Fighter or Marvel vs games. The Alpha series, and SF's IV and V have about a fourth to a third each--roughly--of Final Fight characters in them. Street Fighter III even had one.

Capcom's biggest competitor in the fighting games genre was SNK. Even other competitors who made Street Fighter II clones often did so on MVS hardware, like World Heroes by ADK, Breakers by Visco, or the Fighters History games by Data East, so I won't mention them specifically (most of them never advanced beyond Street Fighter II-like anyway.) SNK used the same hardware for the better part of two decades, so they never really increased their technical capability until they finally abandoned it after the turn of the millennium. However, that doesn't mean that every game used the same style of artwork, and different series had more or less attention to detail, realism vs cartoonishness, etc. I'm going to call all of this a single generation, although there are some notable things to point out as brackets within that generation.

1. MVS generation. A lot of different graphical "tricks" were tried, even fairly early on, like Art of Fighting's zoom feature. Fatal Fury itself has the most primitive graphics of the series, although it's not really much less primitive than Street Fighter II. However, after the release of Street Fighter II, the art style was done more in open imitation of SF2's style, and games like Fatal Fury 2/Special, for instance, look like SF2 clones in terms of style. While always somewhat stylized and comic book like, or animation-like in style, it's fair to say that most of the games of this era approached a semi-realistic look within the animation gamut. A notable exception here is the direction that the Real Bout games went for Special and 2, where they had a much more stylized, cartoon-like appearance that (I believe) was probably done in deliberate imitation of the Alpha style of Street Fighter games. Unlike Capcom, SNK didn't just reuse aging sprites, but constantly updated them and often made them better-looking over time without really changing the style over much itself. If you look at an early King of Fighters game, like 94 or 95, for instance, and compare it to a late MVS (or even Atomiswave) titles like King of Fighters 2002, 2003 or XI, or Mark of the Wolves, you'll probably notice that from a technical standpoint and a stylistic standpoint, they all look quite similar, but you'll also (I believe) quite easily note that the later titles look "better"; the artists just got better over more time and practice with the system, and were able to put out better looking works. That said, the home ports did employ some additional graphical "improvements" including 3D backgrounds (not always better than the 2D ones, but sometimes they were) and pixelation smoothing of the sprites. There was also very notable and noteworthy improvement of the character portraits after matches, during menu selection, etc. as a more comic bookish or anime approach was adopted. Anime is more than one style, however--the anime style that SNK adopted is one that is closest in appearance to western art and animation, while still having an eastern "anime" edge to it. It's less Sailor Moon and more Jim Lee, if you will. This is maybe a little hard to describe as western comic book art and animation and Japanese manga and anime art have cross-pollinated each other to such a degree that its often not easy to say what western animation looks like anymore, other than it certainly excludes the more cartoonish giant-eyes anime and bizarre emotional overreaction cues. But hopefully you can follow what I mean here.
2. After SNK's bankruptcy, all of their titles except King of Fighters basically shut down. XII and XIII were the last 2D fighters, but they feature greatly improved graphics in much higher resolution. I'd say that in most respects, they are comparable to the UDON graphics of Ultra Street Fighter II, but a bit more anime and caricaturish on occasion in style.
3. They didn't stick with that style for very long, for whatever reason (probably because somebody figured out that 3D was cheaper and faster and more flexible.) For XIV and the upcoming XV, they've switched to 3D models. These models are much better than anything Capcom have used, in my opinion; although they are still more "realistic" "western" anime in style.

Given what I thought about Capcom's styles, you'd think that generation 2 would be my favorite, and you'd probably be right. However, I think that SNK did their 3D animation (after they got the Maximum Impact series out of their hair) better than Capcom did in general, and it's hard to fault their 3D animation. With one exception. SNK has always been known as being "stylish" compared to Capcom. Stylish in this regard is a very Japanese thing, though, taking a lot of inspiration from "Japanese Street Fashion". I suppose there's nothing to call that other than "stylish" compared to Capcom, but whereas stylish would seem like a compliment, here it isn't. Japanese street fashion, to western eyes, looks like what a horde of flaming gay people would wear if they all decided that they were really nerdy and wanted to go to Comicon via some kind of goth/steampunk niche. These character and costume designs that SNK comes up with are not cool. They're not good. They're bizarre. SNK has always had that reputation, but it's gotten orders of magnitude worse in the last few titles compared to what it used to be during the "glory days" of mainline King of Fighters titles. 

Luckily, enough characters have enough history that they can't deviate too much from their look without upsetting the fans, so this mostly applies to the new characters that they keep adding rather than the older ones that they're still picking up because they're perennial favorites. This limits the amount of damage this bizarre aesthetic can wreak on the series, but as time goes on, it's probably going to get worse.

As an aside, it's worth pointing out that the King of Fighters XIII cast was one of the most conservative, traditional ones done in many years, which also limited the ability of the "SNK aesthetic" from being very prominent in that game. Yet another reason to like generation 2.

For beat em ups, Sega's Streets of Rage was obviously the main competitor to Final Fight. Those two are usually considered the epitome of the beat em up genre. Normally, I wouldn't think a comparison here would be necessary. Streets of Rage was sub-generation 1 in comparison to Capcom, while 2 and 3 were comparable to Final Fantasy and therefore to Street Fighter II in graphics.

However, in recent years, an indie publisher convinced Sega to let them publish Streets of Rage 4 out of France of all places, and they've done a fabulous job with it. I highly recommend watching a youtube video of a playthrough of it. While the art style is sometimes quite anime, at other times, it's more reminiscent of western comic book or Disney style art. In any case, at all points, it looks absolutely fantastic, at least as good as Capcom's generation 5 or SNK's generation 2, and similar in many respects to both... but probably actually better. Capcom's generation 5 still tried to just upgrade technically while copying faithfully their generation 2 designs, and SNK's generation 2 was a little too out there with caricaturish anime stylings. Streets of Rage 4 does everything that those do, except without the weaknesses. 

If I could see fighting games done the way I'd most like to see them done, then the lizardcube style from Streets of Rage 4 would be it. The ONLY thing that I can complain about with Streets of Rage 4, and I'm not 100% sure that I'm willing to complain about it until it gets even worse, is its bizarre Diversity, Inc. cast with way too many women acting like men and way too many bizarre ethnic groups. Why is the one guy a Maori? Do you know how many Maoris I've seen in America in nearly fifty years of living here? Other than a handful of students at BYU Hawaii, absolutely ZERO. Anyway, I think it's on the cusp of being a problem without quite managing to become one yet at its current state.

Anyway, I've posted this before, but here's a mockup that the lizardcube guys did of a Mark of the Wolves 2 done in their Streets of Rage 4 style. I'd love to see some fighting games get this treatment. Absolutely.