The Zelda games actually had different artists throughout the years. In the beginning it was Yoshiaki Koizumi and former anime studio employee Yoichi Kotabe that worked on the first few Zelda games. However Metroid artist mainstay Yusuke Nakano is the most popular one due to his work on Ocarina of Time (which was his firstZelda project). Later he did Majora's Mask, the Oracle games (for a guy inspired by Kotabe's work on Link to the Past and Link's Awakening for his work on Oracle of Ages/Seasons he didn't do too bad), and his work on Twilight Princess (2006) shows how his style improved drastically since Ocarina of Time (1998).
Yusuke Nakano also did the artwork for The Wind Waker. It's also noticeable: Look closely at the artwork in the instruction booklet and you will find the way the outlines are drawn to be quite similar to the artwork of Ocarina of Time and Twilight Princess. Even though it Super-Deformed, it's still his style. Nakano himself stated in an article, that he liked working on Twilight Princess the best, because he is into this kind of fantasy art, but found The Wind Waker to be an interesting experience as well, because of the drastic change in style.
However, you can even notice it with Links that are the same characters. Ocarina of Time Link has gone from having small pupils and a long nose to gigantic pupils and a small nose, from the original game art through appearances in spinoffs, to the 2011 3DS remake.
With a HD-remake of Wind Waker you can see a direct art evolution here. More drastic art evolution is present in the 3DS remake of Ocarina of Time, due to the fact that technical limitations prevented the N64 version's graphics from resembling the game's official artwork.
Street Fighter has had noticeable art shifts within the various incarnations of just the main franchise. The original game used character designs that were more realistic than cartoony, albeit with pretty sparse animation. Its sequel, Street Fighter II, was running on the same style, but had bigger sprite size, more frames of animation and slightly deeper details. Realistic design was thrown out entirely for the prequel Street Fighter Alpha series and the characters all took on a more anime-inspired look that also led to a few looking noticeably different in both costume and builds. Street Fighter III backed away from this and returned once more to more realistic designs. Street Fighter IV appears to be looking to blend the two concepts by maintaining cartoony facial expressions but otherwise returning to more classic, realistic character designs. However, many characters are noticeably a lot more muscular.
Bubble Bobble: Bub and Bob have basic 8-bit sprites in the original. For Part2, they only have their color and white for their sprites but get a simplified outline and a new short square silhouette. Bub and Bob get nicely shaded yet still keep their silhouette for Bubble Symphony. They get brighter shades and get a slimmer silhouette for Bubble Memories, in which by that time they don't have literal-black-line-struck-out eyes upon death anymore — their eyes go missing.
Puzzle Bobble/Bust-A-Move: The 1st game follows yet slightly improves the original Bubble Bobble sprites. The 2nd game follows the Bubble Memories' sprite style (as both games were released around the same time). The 3rd game has an Anime style, and the 4th game goes back to the 2nd game's style.
The main artist for the Shin Megami Tensei franchise is Kazuma Kaneko, and has been almost since its earliest era. He used to have a more traditional, generic anime style. Then around the late 90s, the man discovered Adobe Photoshop and dramatically altered his art to the porcelain doll look that the franchise is usually associated with. You can see this shift at its most dramatic by comparing how a character he drew for the original Persona looks in the first game◊ and Persona 2after the art change.◊
The release of Pokémon Black and White is also accompanied by a new art shift: while protagonists Hilbert◊ and Hilda◊ seem to hearken back to the art style featured prominently in Generations III (i.e., Brendan◊; May◊) and IV (i.e., Lucas◊; Dawn◊), the artwork of Unova Gym Leaders such as Cilan◊ and Iris◊ shows a marked change in drawing style.
The Gym Leaders, Elite Four and Champion in Black & White weren't handled by Sugimori. The player characters and N were, however.
Shinkiro, a video game artist for SNK and Capcom, has had his style change dramatically over time. His early work, such as for Fatal Fury and The King of Fighters have some realistic touches but still look hand-drawn for the most part. Later on, his work (for example, the cover for Samurai Shodown II, the SNK-style artwork in the Capcom vs. SNK series) became very realistic, while avoiding some details to avoid going into the Uncanny Valley. His current style, seen in Tatsunoko vs. Capcom, is a mix of both, almost appearing as cel-shaded. Though early on, it is an evolution in art, he attributes his current style to his preference to draw digitally nowadays. His art is immediately recognizable in all styles, though.
The same could be said of other SNK artists. Compare the earlier work of Shinkiro's protégé Hiroaki (Fatal Fury: Wild Ambition, Buriki One, The King of Fighters EX and EX2) to his illustrations in KOF '94 Re-Bout, KOF XI, KOF '98: Ultimate Match, and even projects outside of SNK such as God Hand. Like Shinkiro, his overall style has been consistent throughout the years, although his drawings in KOF 2002: Unlimited Match and KOF Sky Stage have the characters looking a bit more youthful than before.
Even the designs themselves have had changes. Originally his arms and legs were very lanky◊ and long◊. He has since become more compact◊, and his limbs more shorter, to the point where in the Sonic Unleashed beta he was his classic design with green eyes; his fur color was also darker in the early to mid 2000s. Likewise his classic design went through various changes, most obvious to westerns the change from his original Western design◊ to his Japanese design◊.
World of Warcraft has gotten progressively more stylized since the game first came out in 2004. Early weapons and armor were fairly mundane and realistic, while newer items are larger, more colorful, and more extravagant.
Until you hit "Wrath of the Lich King". While these items are larger, they seem to have turned the trend upside down in terms of coloration and texturing — nearly all Wrath armor is drab (to avoid Clown Suit armor) and textured in a semi-realistic way. Case in Point: that horse you can buy from the argent crusade. It's the direct opposite of the happy, fantasy, colorful paladin mount — drab and gritty.
But once again true in the last few raid dungeons. Sure, most of the generic armor is drab, but the Tier sets and the high end weapons take the grimdark thing and run straight int the realm of flashy evil looking weapons and the tier10 armor is all based off various undead monsters.
Since AdventureQuest has been adding new content every week for years and hiring more and more decent artists along the way, the art has changed a lot. There's even a page in the forum-based encyclopedia showing the old versions of monsters that have been redrawn. The differences◊ can be◊ memorable◊.
Even the ones that haven't had their basic design changed can look very different; their Mascot Mook the Frogzard went from this◊ to this◊. They revamped a lot of old low-level monsters at the same time, such as the Arroc, formerly this ugly thing◊ into this◊, which actually looks kinda cool.
The artwork from series creator ZUN is (memetically) considered to be horrible. Sometime after Subterranean Animism his drawing skills began to improve quite a bit.
Final Fantasy VII's designs and art style in the original PlayStation game are extremely anime-like and cartoony. The recent Compilation games have dumped that for a heavily realistic style. Even when you take into account the loss of those awful polygon characters its still a huge shift. Compare the artwork from 1997◊ to 20◊07◊.
There is a pretty noticeable chain of art evolutions in Nomura's work, seen in about three different phases: his pre-1999 stuff, when he drew mostly lego-people, his "Belt and Zipper" years where people were slightly lanky and had very detail-heavy costumes, and his stuff starting from the Compilation of FFVII on, where the black outlines of characters have more weight (and in some games, replace color shading) and more attention is given to poses and colors rather than clothes.
Star Fox goes through this a lot. Fox's outfit in particular seems to be completely redesigned every game.
Mutsumi Inomata, the artist most frequently used for character designs by Namco for its Tales Series, has really refined her art style as the series has progressed. Her work has gotten more detailed and the proportions have improved (many of her early character designs look anorexic), she uses more vibrant colors, and male characters (usually) look less effeminate. Compare Leon of Tales of Destiny's character artwork from the original game to that of his updated artwork in the remake.
Trolls in the Warcraft series have had their appearance change a little bit throughout the years. In Warcraft II, they had 5 fingers, only Berserkers seemed to have tusks, and their ears were much shorter. In Warcraft III they now had three fingers, almost all trolls had tusks, and their ears were longer and more exaggerated.
High Elves also had this happen to them. In Warcraft II they had normal eyes, regular eyebrows and short pointy ears. In Warcraft III their ears were long enough to poke someone's eye out, their eyebrows were similarly long, and they had blank white eyes. Their appearance changed again in World of Warcraft: the Burning Crusade and now they all had blue or green Glowing Eyes of Doom.
Also, their designs became almost Animesque when they were made playable in Burning Crusade.
While still primarily stick figures and simple illustrations, revamped zones in Kingdom of Loathing will often get new art of better resolution and detail.
The Ace Attorney series' art has changed a lot over the past 10 years. Compare 2001 Phoenix◊ and 2004 Phoenix◊ or Demon Prosecutor Edgeworth◊ and Edgeworth in "Ace Attorney Investigations"◊. It's extremely noticeable in the games themselves, due to their tendency to reuse sprites from the first games in the later ones. By the 4th game, the new sprites look so incredibly much more impressive that the old characters appear to be downright ugly standing next to them. Maya suffered from it the most, to the point that she was almost unrecognizable as herself when she had a new pose, "just exorcised and exhausted", added to her sprite repertoire in the 3rd game. The new sprite looked a whole deal better than all of her other sprites. Also, in her Maid spriteset, the differences between the shading on her body (old) and on her clothes (new) are painfully obvious. Problems like this are avoided in the most recent game, Ace Attorney Investigations, which had all Sprites redrawn from scratch, even those of old characters.
In Dual Destinies, the series made the jump to cel-shaded 3D models instead of sprites and added fully animated and voiced cutscenes produced by Studio BONES. Some returning characters have had their designs changed slightly, such as Phoenix gaining a waistcoat and a strand of Idiot Hair. Despite this, the animations of the returning characters mimic the animations of their old sprites, and the new characters are animated in a way that resembles sprite animation.
Series 1 and 2 of Telltale Games version of Sam & Max: Freelance Police had a semi-cartoony but perfectly workable fitting style. Come season 3, The Devil's Playhouse, and the same style is around, but with added textures on the backgrounds, much more detailed and complex animation, details on the characters themselves (such as Sam having realistic textures on his clothes and saliva on his tongue, and Max having a crease down his back where his spine is) and a nice noir-style grimey filter over everything. It's quite a jump to go from one directly to the other.
In 1992, when Kirby's Dream Land was brought to America and Europe, Kirby was colored white both because Nintendo's American and European divisions figured pink wouldn't sell and because of the monochrome Game Boy would only show Kirby as white anyway. Starting with Kirby's Adventure, he's been allowed to remain pink in all regions. Also during the 90's, he was very big and fat-looking, with pointy hands, and very small eyes and mouth. From Kirby Super Star for the SNES to Super Smash Bros. for the N64, his appearance began to be refined with a smaller, less bulky body, and rounded hands; his eyes and mouth became bigger and he gained dark blue irises.
The Umineko no Naku Koro ni sound novels has roughly the same art through all episodes but instead the intro is the thing that evolves (though it is more his use of CGI and movement that is evolving not the ground artwork). Just compare the intro to episode 1/2 and ep 3/4, also look at the opening for 5/6 and 7/8 which evolves it even further. Though be warned that it is slight spoilers in them.
The Living Books games started with some basic graphics (the characters had no shading and had noticeable aliasing). The animations were also basic and were normal sprites moving across the screen. As time moved on, the characters started to look like actual illustrations, and the animation got more complex.
Looks like Mario actually lost some of that weight nowadays, didn't he?
In the later two NES / Famicom Super Mario Bros. games, the sprites are drawn with dark outlines (dark blue in Super Mario Bros. 2, black in Super Mario Bros. 3) along the edges and sometimes also along the border between differently-colored areas, whereas the sprites in the first game and The Lost Levels don't have these outlines. This was part of a larger trend in sprite-design style that occurred throughout the lifespan of the Famicom console. (Incidentally, in the NES port of Mario is Missing!, which also used black outlining on its sprites, Luigi's sprite looks like the one in Super Mario World, redrawn to meet the color palette limits of the NES.)
Every Mega Man series has undergone a noticeable change over the years. The classic series started with artwork of rather crude, chibi-esque character designs that progressed into a more serious and detailed style over time, reaching its peak with the 8th game. When Mega Man 9 and Mega Man 10 came out for the Wii, the time gap between new games led to a hybrid of both the class NES-style artwork and more detailed SNES/Playstation era Mega Man. The original in-game sprites, however, haven't changed much at all, aside from lone games that were on more consoles that had better graphics to work with. The Wii downnloadable games actually revert back to the original sprite style out of nostalgic reverence. Plus, it's cheap.
Mega Man X has official art with a very distinct cartoonish, almost 80's shonen feel in the first few games, notably the original. As the plots of the games turn increasinglly dire and the platforms for each change, the art detail dramatically spikes. In that same vein, so the game sprites, first subtle changes, then major alterations to in-game sprites as the console graphic capabilities are ramped up.
To take it into perspective, the "classic" style designs are used from the first game to Mega Man X3, growing more pronounced in detail with each sequel, along with sprites that have more elaborate, shaded coloring (very noticeable in X3.) Mega Man X4 marks the jump to PlayStation, where the characters gain sterner, toughened looks that reflect the darker nature of the plots, and the sprite artists try to replicate their appearances in respect to their artwork as faithfully as possible with immense details. By Mega Man X6, the sprites even undergo slight palette changes to more accurate colors. Mega Man X7 is the first game to be on a 3D platformer, now shifting to polygon models and a few updates to character designs. Mega Man X8 goes as far as to give the Reploids lankier, humanoid-proportioned armor and smaller, oval-shaped eyes, but these changes are disregarded in Mega Man X: Command Mission — though this time, X sports new body armor and a Scarf of Asskickingout of the blue.
Mega Man Zero has a similar change in art. Faces seem a bit more circular and puffy in the first game, but by the last game, their appearances are more angular and unique, especially Zero. In the inital game, he's sporting generic, determined expressions, but remarkably hardened, stern, and outright badass by the final game installment. The mugshots, too, reflect changes. The initial game actually used rough concept art for the mugs, but the later games have sharper and cleaner pixel art ripped straight from official art or done by hand.
Mega Man Battle Network changes art style in between 3 and 4. The character's eyes are rounded instead of semicircular (most prominent on Mega Man) and the shapes of their bodies feel more slender and less blocky, though the Navis are prone to some wacky, far-fetched designs. The games themselves shrink down sprite dimension and gain thick outlines to create a crisp feel of objects. Mugshots also change considerably, going from fairly Off Model to almost spot-on by the last game.
Felicia from Darkstalkers was originally voluptuous in the first game. In Night Warriors, she was a rather frightening creature. By Vampire Savior, her looks had been finalized.
The community-made games for Unlimited Adventures. The oldest are very much subject to Sturgeon's Law, while the newest ones are much better. This is caused in part by technological evolution (better graphics editors, etc.)... and in part, unfortunately, by the community dwindling to a few most experienced and oldest fans.
Halo has this by virtue of how long-running the series is. It is most notable with Master Chief and the Mjolnir Armor design. The first game it looked like a completely closed off armored suit while the later games gave it a stretchable fabric suit with the armor layered on top. Even with the Halo: Combat EvolvedAnniversary Edition they strove for a look that was true to the classic look and not just completely redesigning it to better align with the prequel Halo: Reach. By Halo 4 they decided to go ahead with a complete design Retcon.
Sly Cooper and the Thievius Raccoonus looks quite different from further entries in the Sly Cooper series. Sly looks more cutesy, Bentley's clothes are different, the graphics themselves are more simplistic, and the cutscenes are very crudely-drawn and animated, compared to the smooth artwork and animation that the other games gave.
Professor Layton went through subtle yet noticeable changes in artstyle as the series went on (and its budget increased). It's more noticeable with Luke — between the first◊ and the third◊ games, his face became rounder, his hairstyle became more defined, and his proportions became less noodley note You could pass it off as aging, but do note that Unwound Future Luke looks markedly shorter than he did in the first game. Layton himself got similarly more well defined, coupled by artwork that started showing him from different angles. The animated cutscenes were also noticeably improved (compare how they are in the first game◊ to how they would be later on◊)
In Quest Of Yipe, the first game has very crude and flat graphics, to the point that your player is a stick figure. The sprites become a little more involved and gain shading in the second game, and the art takes a major leap in the third.
The character appearances in Saints Row change significantly between 2 and The Third.
Every Fire Emblem game has different artists (or one artist for one saga, namely Tellius), but Intelligent Systems clearly didn't get an actual artist until the Jugdral games.
In Robopon, in a special version of Moon, the sprites for some Robopon were altered. Some new looks transferred to Robopon 2.