Evolutionary Retcon



Over the course of time, advances in special effects technology and makeup techniques can allow a series to have bigger and better creatures and monsters. Often, the original version of a creature might not have been that cool or interesting, and so a new model was established using the more advanced technology. In other cases, technological advances can't be credited for the retcon: sometimes a creature's look will change as a series progresses due to Art Evolution.

This is often seen in fantasy or Sci-fi media.

Film

 * The xenomorphs from the later Alien films are much more insectile and predatory than the original film's man in a suit version.
 * An inversion occurred with the Star Wars prequels. When he first appeared in The Empire Strikes Back, Yoda was created with puppets. In Attack of the Clones, Yoda was created using 100% CGI and large portions of the fan base revolted, preferring Frank Oz's puppetry.
 * Jurassic Park 3's raptors are brightly colored and frilled as a nod to the then-recent discovery that they had feathers.
 * By the third entry in Peter Jackson's The Lord of the Rings series, he'd decided he wasn't a fan of the "witch noses" on certain orcs in the previous films. As a result, none of Return of the King's orcs sported long, pointy noses.

Live Action TV

 * In Doctor Who, the original Daleks were clunky and, because they were mounted on tricycles, had difficulty with rough terrain. And stairs? Forget about it. CGI allows the new series to feature flying Daleks who are capable of traversing stairs and interstellar space without trouble. Heck of an upgrade there.
 * The Cybermen also became much more menacing looking and ominous.
 * Another Doctor Who example: the Macra. Old series Macra look like this. New series Macra look like this.
 * The Silurians in the old series were done with rather clunky (and practically immobile) masks. The new ones are still created with makeup, but it's far more sophisticated and lifelike. However, the old ones were more alien, featuring sucker-like mouths and three eyes. The new ones look more like green, scaly humans. This is acknowledged in-show as being different subspecies.
 * In Buffy the Vampire Slayer, Oz's wolf form went from an animatronic to a much sleeker full-body skunk-wolf suit.
 * The Klingons in the original Star Trek the Original Series series were basically swarthy Human Aliens, but advances in makeup technology allowed them to become one of the best (and most believable) examples of Rubber Forehead Aliens. This example is notable in that Gene Roddenberry always claimed that the "new" Klingons were how they would have looked back in the 1960s if it had been possible at the time.
 * It's worth pointing out that Worf's makeup alone improved significantly after the first season or two.
 * Trek's Borg also received an upgrade in Star Trek First Contact, losing the chalk-white skin in favor of glistening, apparently decaying flesh.
 * Pratically everything about the look of the Borg and their ships was completely redesigned for First Contact. Due to the limited special effects budget of the TV series, the costumes and models used for the Borg in the series were not as detailed as the filmmakers would have liked and would not have looked up to par with the rest of the movie's effects when seen on the big screen. With the movie's larger budget, much more detailed costumes were able to be created for the movie.
 * Romulans as well; in TOS and some early TNG, they're basically indistinguishable from Vulcans. In later seasons of TNG and all following seasons, they have a distinctive V-shaped ridge on their foreheads.
 * However, a few examples suggest that the smooth-headed Romulans were not retconned into oblivion: at least two Romulans have appeared undercover as Vulcans (lacking forehead ridges), one of whom later appears in Romulan garb still lacking the ridge, and notably, Spock is able to pose as a Romulan on the planet Romulus itself without his Vulcan heritage being revealed, suggesting that some Romulans still lack forehead ridges, though they are in the extreme minority.

Video Games

 * The Covenant from the Halo series have become more life-like and more scary-looking as computer animation technology has improved.
 * Dragon Age II's qunari now sport horns in order to differentiate them from the other races. The official explanation as to why the qunari seen in Origins don't have horns is that the qunari who are naturally born hornless, such as Sten and the members of his squad, are considered special and are given special tasks, such as scouting foreign lands, while the other qunari seen in Origins are Tal-Vashoth mercenaries who typically remove their horns when they leave the qunari.
 * The hurlocks have also changed, appearing a few shades lighter, smoother-skinned, and with blunter teeth in the sequel.
 * In the first Metroid, due to graphical limitations, Kraid and Ridley only look as high as Samus. By the time Super Metroid came around, Kraid was two rooms high, and Ridley was at least three times the size of Samus. Zero Mission retcons the Super design into canon.
 * Deus Ex: Human Revolution, more than 10 years since the original Deus Ex, has mechanical augmentations that are significantly more advanced and useful than the un-lifelike ones in Deus Ex. The excuse is that this is right before a great collapse which occurs prior to the beginning of Deus Ex and before the rise of nano augmentations.
 * Practically every memorable demon in the Doom series was completely redesigned for Doom3. Most of these redesigns made the demons appear much scarier and more formidable opponents for the player. The original imp, for example, was a large, brown creature with spikes on its shoulders that would slowly advance towards the player while hurling fireballs at them. The new imp is a slimmer grey creature with no spikes and ten eyes on its head that is capable of climbing walls and has incredible jumping ability that allows it to clear the distance across an entire room in a single leap and generally attacks with a much more aggressive style.