Actionized Sequel

A new film franchise has a lot of work to do. In only a couple hours, you have to introduce the characters, the premise, and all the Phlebotinum you're going to be using for the rest of the series, and you need to have a plot to tie it all together. Because of this, the first installment in a film series tends to be slower paced.

Starting with the second film, though, most of the Backstory and Everyone Meets Everyone is out of the way and the budget for the movie is often much larger, allowing it and subsequent sequels to fall increasingly into the 'Action' genre, even if the original didn't have that much action. If it did, the sequels become outright over the top in their action.

Tends to happen with horror films. Occasionally, as with Alien, it's because the director feels the first was perfect and tries to do new things. Other times, it's because anyone who survives a horror movie graduates with a few levels in badass, and when you put a Badass into a horror movie, it becomes an action movie.

This can also happen in some video games, particularly those in the horror genre. Often, the first installment will be based on survival, not combat, and encourage you to avoid the enemies rather than fight them directly. Possibly in an effort to appeal to a wider audience (after all, Survival is hard, but blasting shit is fun), subsequent games will add more ammo and weapons, or go into a full Genre Shift. Of course, it can happen to other genres as well.

Fanfic

 * The My Little Pony Friendship Is Magic fanfic "It's Always Sunny in Fillydelphia" involves Applejack going on a date with Soarin of the Wonderbolts (her only customer in the season 1 finale "The Best Night Ever") and the two of them falling in love. Its sequel, "Semper Fidelis", plunks the two of them in an action-packed adventure inspired by the G1 My Little Pony special "Rescue at Midnight Castle".

Film

 * First Blood was a moody piece about a troubled Vietnam War vet trying to adapt to a regular life again and failing disastrously. Rambo: First Blood Part II and Rambo take that vet and put him back where he is killing people and taking names.
 * Terminator is a horror movie about being chased by an unyielding, unstoppable menace. Terminator 2: Judgment Day is ROBOT FIGHT CITY.
 * It arguably retained the horror elements, considering the T-1000.
 * Alien is a suspense movie about a creature hidden in the labyrinthine corridors of a space ship. Aliens sends in the clones for all-out war. This was because James Cameron (who also wrote Terminator 2 and Rambo) thought Alien was perfect at what it did and wanted to do something different. Notably, Aliens is considered a great film in its own right, and some consider it even better than Alien.
 * The Batman films subverted the trope, defied it, and then played it straight. The first movie (in 1989) had to set up a lot of plot exposition and could get draggy at times, but it still had a fair amount of action. Its sequel, Batman Returns, had even more action, but paradoxically seemed less action-packed because the non-action sequences and story themes were so powerful. Batman Forever and Batman and Robin both had tons of action, often for no other reason than to have an action sequence.
 * Casino Royale to Quantum of Solace - Even though the first was an action movie, the sequel did take this to ludicrous proportions. The Jittercam didn't help.
 * Pitch Black to The Chronicles of Riddick
 * The first X-Men 1 movie had a few fight scenes, but much of the screentime was devoted to explaining Mutants, and setting up the character relationships. X-Men United, however, finally let Wolverine really cut loose, and The Last Stand has a few full-on mutant rumbles.
 * Parodied by Family Guy with The Passion of the Christ 2: Crucify This! (which from the trailer appeared to be Rush Hour with Jesus instead of Jackie Chan)
 * The Mad Max progressively movies added more action with more budget.
 * Koi...Mil Gaya starring Hrithik Roshan is a Filmfare Award-winning movie about a developmentally disabled young man (Roshan) who tries to continue the work his father did in communicating with extra-terrestrials from outer space, which leads to something miraculous and wonderful. Its sequel Krrish? That young man's son (also Roshan) was given his dad's superpowers and becomes a superhero, Twenty Minutes Into the Future.
 * Parodied in Jay and Silent Bob Strike Back, where Ben Affleck and Matt Damon are seen to be filming Good Will Hunting 2: Hunting Season. Will Hunting uses a shotgun to end arguments.
 * UHF shows a preview for the fake movie Gandhi 2. All of his arguments are solved with killing his opponents. He likes his steak bloody rare, and the movie title is spelled out as he fires a submachine gun across a restaurant because some said "Hey baldy!"
 * Though not advertised as a sequel, Tim Burton's Alice in Wonderland uses the events of the original book as backstory, with Alice now a young woman who becomes an Action Girl and slays the Jabberwock.
 * Star Trek II the Wrath of Khan in comparison to Star Trek the Motion Picture. In this case, it was generally seen as a vast improvement over the long, slow-paced original.
 * Also, Star Trek First Contact has far more action than earlier films in the series and is often praised for it. Star Trek: Nemesis took it even further, but it was decidedly not praised for it—action is cool, but it shouldn't come at the expense of anything resembling a sensible plot. The 2009 film has been seen as a more action-oriented approach to the series, especially by its detractors, but its action quotient arguably isn't too different than that of the Next Generation films.
 * The original Gojira was a somber allegorical horror film about the dangers of the atomic bomb. The first sequel, Godzilla Raids Again set up the action-based formula of "Monster VS Monster" (in this case, Godzilla VS Anguirus).
 * The sequel to Cars. The first movie was about Lightning growing up and learning to appreciate the people around him in time for a big race. The sequel involves him and Mater being mistaken for American spies by British intelligence, leading to chase sequences and plenty of Stuff Blowing Up.
 * Kung Fu Panda 2 is also this. Thanks to Po getting past his training, he can now join the Furious Five in their missions and become a Rookie Sixth Ranger.
 * Death Wish and Death Wish II were vigilante revenge dramas. Death Wish 3 and Death Wish 4 The Crackdown turned up the action to eleven for the day, with 3 featuring Charles Bronson's biggest bodycount ever.

Video Game

 * Resident Evil 4 and Resident Evil 5, unlike the previous games, have a much more action-packed gameplay style, with fully functional manual aiming, (conditional) melee attacks, and generally more combat-friendly environments. Several fans agree that they are more like action games than survival horror. As one analysis explained, the series shifted from aiming for "scary" to aiming for "tense". Or put another way, it goes from survival horror to adrenaline horror.
 * The actionization of the series may have started as far back as the second game. While the original gave you so little ammo that it really was a better idea to just run away from everything, it's possible to finish the second game with a lot of high-powered ammo left over, which encourages fight over flight.
 * While 2 gives you plenty of ammo, Resident Evil 3 Nemesis is generally a more action-centered game, giving Jill a dodge ability, the means to craft her own ammo, no longer restricting staircase movement to a button press, and, of course, the Nemesis.
 * Code Veronica had Guns Akimbo and manual aiming for some guns.
 * Operation Raccoon City goes even further than 4 or 5: the players are members of a heavily-armed Umbrella black ops team, who mow down zombies with full-auto fire and get into gunfights with US Special Forces.
 * Although not to the same extent as Resident Evil 4 or 5, Silent Hill Homecoming has a much more developed combat system, including combos, a dodge move, and a lock-on camera that turns every fight into a one-on-one duel, that makes combat a much more viable option rather than simply running away from everything like in the first 4 games. Enemy encounters are still spaced out evenly and the game's overall pace is still pretty slow and brooding.
 * Mass Effect 2 has more and faster-paced action than its predecessor.
 * Should check out that Mass Effect 3 trailer...
 * The first Dino Crisis, like the Resident Evil series, focused on survival, and barely gave you enough ammo to deal with the dinosaurs you encountered. The second is a full-on action shooter, letting you slaughter them by the dozens, and rack up combo points to buy ever larger guns.
 * The Final Fantasy series is still firmly in the RPG genre, but has slowly becoming more action oriented, with action commands in battle, and a shift to more real time combat. Spin Offs like Dirge of Cerberus or Crisis Core are a full genre shift.
 * Jak and Daxter was an action game already, but it was more of a standard platformer. Sequels introduced gunplay and somewhat less straight-up platforming.
 * The Neverhood is a claymation-based adventure game with a bizarre sense of humor. Its sequel, Skull Monkeys, keeps the claymation and humor but shifts to a platformer.
 * The Kingdom Hearts series. The first game had about equal amounts of combat, platforming, and puzzle-solving. The combat in the first game was very simple, as you could do basic sword swings, a few spells, a few summons, and by the end of the game Sora gets exactly 4 "special attacks", and upgrading attacks in that game was nothing more than adding a few more hits to his basic swing and making the hits pack more of a punch. The second game - at which point the series had already set forth the motion that Sora was basically The Messiah and now needed to prove just exactly what made a 15 year old boy better than grown, experienced men and women with supernatural powers- focused mainly on combat, with Drive Forms, Summons, much more powerful and varied Spells, Limits, the ability to equip whole new combat techniques as well as being able to upgrade basic swings like in the first game, and Action Commands, which are specialized button sequences unique to every one of the hundreds of different enemies Sora has to fight from the smallest Dusk to the final boss Xemnas that sometimes cause him to perform some incredibly awesome and crushing attacks that whittle away at his enemies and at other times initiate a short sequence of some amazingly athletic maneuvers that can save Sora from an attack (such as jumping hundreds of feet in the air off an exploding ship or the time Roxas-a different playable character- hurled his Keyblade in midair at an orb of death he was falling into).; giving Sora a ridiculous number of ways to kick ass. The next few games put some more emphasis on platforming, but continued to refine the combat system.
 * Inversion: Penumbra: Black Plague nearly completely took down the combat system Overture offered, throwing objects aside.
 * Amnesia the Dark Descent, its Spiritual Successor, takes it up a notch: the only way to get rid of the monsters is to hide from them, or in some cases, run until another area is reached. Some enemies, like a few versions of Kaernk, can be killed, but it's mostly a case of Good Bad Bugs.
 * Inversion: Doom 3 goes from the run and gun shooter, a landmark of the previous games, to a scary, moody, slow horror shooter.
 * While more of a "remake" than a "sequel", Silent Hill: Shattered Memories also throws the combat system out of the window.
 * Splinter Cell: Conviction turns up the action and gives badass Sam Fisher another level in badass.
 * The first two Turrican were slow, methodical Metroidvania platformers while the console sequels and Turrican 3 were fast-paced run & gun shooters more akin to Contra.
 * Metal Gear Solid 4: Guns of the Patriots made the run n gun style of gameplay an option as compared to earlier titles which were more stealth focused and were more difficult to run n gun.
 * The first three Rainbow Six games (Rainbow Six, Rogue Spear and Raven Shield) we about careful planning and one-hit-kill gameplay. Lockdown gave you a health bar and removed the tactical planning part. Vegas and Vegas 2 are about three guys with regenerating health mowing down a massive army of mercenaries and terrorists.
 * Metroid:
 * Metroid Prime 3: Corruption, compared to the first previous two games. There are a lot more actionized setpieces (like dropping a giant bomb on a leviathan shield, the demolition trooper escort mission, Hypermode, the free-fall Ridley fight) and less isolated parts. It is also more linear, but mostly due to level design, as you fly around several planets and the areas are smaller. There is still plenty of exploring to do, but combat takes a strong precedence over it.
 * Other M takes, it even further by giving Samus loads of melee attacks, dodging and other combat-related abilities.
 * The Prime series in itself is one, what with moving from the original platformer style into a First-Person Shooter.
 * Zig Zagged with Need for Speed series: some games are about kicking arses and taking credits in illegal street racing, some others are about professional, Gran Turismo-esque racing. Examples of the former are Most Wanted, Carbon, and Hot Pursuit, the latter are Pro Street, Shift 1, Shift 2.
 * The first Condemned game, Criminal Origins, had firearms mostly as an afterthought- guns were pretty rare, you couldn't reload, and it was entirely possible to go through the game without firing a single bullet. In the second game, Bloodshot, guns are a bit more plentiful, and there are a few parts where having a gun is necessary for survival. The melee elements are also enhanced with the addition of combos and chain attacks.
 * Dead Space 2: the first Dead Space wasn't without it, but it was certainly slower and less over-the-top. To put things into perspective, in the first game Isaac moved around in zero-g by jumping from surface to surface with the aid of his RIG's magnetic boots. In the second game, Isaac moves in zero-g by way of a Jet Pack integrated into his RIG. If you're not drawing comparisons to Iron Man, you're doing it wrong.
 * Towards the end of the Adventure game era and the rise of the FPS genre, Sierra Entertainment attempted to actionize several of their franchises. These games often became the end of their respective franchises. For examples:
 * Quest for Glory V. Whether this would have been a Franchise Killer is unknown, since the game wrapped up the series anyway.
 * King's Quest Mask of Eternity
 * Police Quest is a rare exemption, the games franchise re-inventing itself as Police Quest SWAT and later just SWAT. This series lived on to make 4 more games after their last adventure game precursor.