
The Leprechaun series is more about humor than horror. The various installments are not direct sequels to each other, and apparently there is a different Leprechaun in each movie (although I know from personal experience that there's plenty of room for debate on this point). The Leprechaun in the first movie is more childish than in the rest of the series, but that's fine - it just allows him a wider range of outrageously entertaining behavior.

Leprechaun:
A horrific Leprechaun goes on a rampage after his precious bag of gold coins is stolen. He uses all of his magical destructive powers to trick, terrorize and kill anyone who is unlucky enough to hinder his relentless search. In a frantic attempt to survive the wrath of the Leprechaun, Tory and her friends scramble to find the only weapon known to kill this Irish monster....a four leaf clover. However, until they discover a four leaf clover or return all the gold taken from the rainbow's end, their fairy tale nightmare has only just begun.
Most Leprechaun fans agree that the first movie is the least impressive of the series, but it's lots of fun nonetheless. The plot is extremely simple - "killer Leprechaun terrorizes farmhouse" pretty much sums it up. The movie gets off to a decent start, but then comes a long dull stretch where the Leprechaun is kept hidden in the shadows while the rest of the cast indulges in a lot of unnecessary, repetitive dialogue. This is a big mistake - the Leprechaun is the only thing that makes the movie watchable, and it's no fun listening as Jennifer Aniston whines and that obnoxious kid mouths off. But the Leprechaun eventually comes out into the open and then the entertainment begins, with snappy Leprechaun dialogue and rhymes, twisted Leprechaun games, assorted sight gags, and the occasional bloody murder played for laughs.

Leprechaun 2
A thousand years ago, the Leprechaun left a bloody trail when he ripped through the countryside in search of his stolen pot of gold. Now he's back in the big city using all of his deadly tricks to snare the girl of his nightmares. His bloody quest becomes more deadly when her boyfriend steals one of the Irish monster's precious gold coins. The town soon discovers two dead bodies and a trail of gold dust leads them to the Leprechaun's lair.
Well, that's what it says on the jacket. The actual plot is somewhat different. The Leprechaun was cheated out of his bride a thousand years ago, and now he's in Los Angeles plotting to marry Bridget, a descendant of his original bride. Bridget's boyfriend Cody accidentally gets hold of one of the Leprechaun's gold coins, and a cat-and-mouse game ensues as the Leprechaun tries to retrieve the coin and Cody tries to retrieve Bridget.
The magically malicious Leprechaun is more sophisticated than he was the first time around, and he has better dialogue, more jokes and rhymes, and a lot more screen time. The first movie had crazier sight gags, but there's still plenty of fun, such as the Leprechaun getting drunk in a bar. The killings are more creative than in the first movie; there's still some graphic gore. This was the first installment of the series to include female frontal nudity, which continued to be a standard feature in the subsequent movies.
It was also the first movie to have an alternate title. It was called One Wedding and a Lot of Funerals in the UK.

Leprechaun 3
He's back! The Leprechaun is on the loose again, this time trying his luck in Las Vegas. The terror begins when a young college student (Scott) gives a beautiful magician's assistant a lift into town.
Once in Vegas, Scott can't resist taking a turn at the roulette wheel. He has a run of bad luck and loses all his money. To win it back he decides to pawn his Rolex watch, but while at the pawn shop he finds one of the Leprechaun's gold shillings. A single piece of Leprechaun's gold, he discovers, will grant the fondest wish of the one who holds it.
Thanks to the lucky coin, Scott goes on a winning streak. Unfortunately, the Leprechaun know his coin is missing and he will gladly kill to get it back.
This movie has a more complex story than Lep 2, and is further removed from reality. It features a variety of shady characters competing with the hero and with each other to try to get possession of the Leprechaun's magic coin. As in all the Leprechaun movies, the acting is bad and we see too much of the people and not enough of the Leprechaun; consequently, the movie drags at times. Still, some of the human characters are fun, like Fazio the bumbling magician and the two low-rent gangsters. On the whole the dialogue is pretty lame, as usual, but for the first time in the series the human characters do get a few funny lines. The Leprechaun is still the undisputed star of the movie, and it all just adds to the fun.

Leprechaun 4: In Space:
On a planet in a distant galaxy, a power hungry Leprechaun holds a beautiful alien princess hostage in order to marry her for her royal title. With her title and his beloved gold, he'll be able to rule the universe. While making his maniacal plans, what he doesn't count on is an invading platoon of marines from Earth to save the princess and foil his plans. An accomplished trickster, the Leprechaun stows himself away on the orbiting spaceship and wreaks havoc on the crew in an attempt to recapture his bride.
Leprechaun 4 marks a departure from the formula that made the series famous, and met with mixed reviews from the Leprechaun fanbase. Some people think it's the best Leprechaun movie ever, while others, including some very devoted fans of the series, are not exactly thrilled with it.
Apart from the killer Leprechaun on the rampage, the characters and situations in the first three movies were more or less based on real life. The fourth movie would be a far-out, futuristic fantasy even if the Leprechaun wasn't in the story. It has the most complex plot of the series, and the large cast of human characters includes some very strange individuals who are utterly unlike anybody you would ever meet in the real world. A lot of time is spent on developing the personalities and relationships of all these people.

Leprechaun in the Hood:
The year is 1993 and the Leprechaun has been awakened from a 20 year nap by four young rap artists looking to make it big.
For the last 20 years the Leprechaun has been kept under wraps by Mack Daddy O’Nassas, a Suge Knight-style hip hop impresario who rose to super-stardom when he discovered the Leprechaun’s gold in 1973. But now the Leprechaun’s golden flute has been stolen from Mack Daddy and he must get it back before the Leprechaun and his Zombie Girls do. Will Mack Daddy get the flute back, or will Stray Bullet, Postmaster P, Butch and Wreck keep it from him and the Leprechaun and make it to Las Vegas for the big talent show?
Leprechaun in the Hood is radically different from the first four movies. Despite some surreal touches in the opening sequence and some other light moments, it's basically a straight horror movie rather than a camp cheesefest. Although it does have Leprechaun rhymes and some jokes and sight gags, on the whole it's quite serious. Most of the time, the Leprechaun acts purely sinister, without the demented glee that we're accustomed to. He's also a lot more patient and methodical than his previous incarnations.

Leprechaun Back 2 tha Hood:
The Leprechaun is back in the hood, all blazed up and seeking revenge! When a group of friends discover his treasure, they soon find out they've unleashed a can of demented whoop ass! With their stack of riches, they go from poor to ghetto-fabulous overnight, spending their newfound loot on pimped-out cars and hair extensions. One by one the friends stand up to the weed-smoking, knife-wielding, car-stealing Leprechaun who will stop at nothing to get his treasure back. Evil has a whole new rap and the kids from the hood had better watch their backs!
More than 3½ years after the last movie, the Leprechaun has done it again! The Leprechaun series has always been remarkably flexible, allowing just about anything to happen without having to worry about what occurred in the previous movies. This film fits in perfectly with the first five; it retains the overall feel of a typical Leprechaun movie, while having a unique flavor all its own. For the first time in Lep history, an animated sequence is part of the film, and it's quite entertaining. But most importantly, the sense of fun that drives the whole series is fully represented here; this movie is a fan-pleaser! The title makes the movie sound like a sequel to the series' fifth installment, Leprechaun in the Hood, but it isn't. Although it's basically set in the same neighborhood, it's a completely different story, and the only character who carries over from the previous movie is the Leprechaun himself.
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"As a rule, men worry more about what they can't see than about what they can." -- Julius Caesar