Lost Boys
Opening Scene
We fly in from low over the sea in the evening to the Beach Boardwalk.
The Vampire Punks cause a minor disturbance on the carousel, which has small children riding as well as adults.
The security guard runs in fear before being taken by an unseen, powerful and airborne entity.
Credits Opening Scene
We observe the Emersons in their 4x4 as they enter Santa Carla in their vehicle. The boys' parents have divorced and they are moving to Santa Carla to live with their mother's father. The carefree and optimistic atmosphere lasts only a few seconds, before again the happy/friendly/welcoming sunny beach carnival aesthetic is juxtaposed and subverted with disturbing horror elements (smells like a dead body, murder capital graffiti, 'People are Strange' etc.)
We see punks, goths, a girl licking a rat, people looking sad, sketchy etc., as well as a jolly holiday-goers in bright clothes. And missing child posters. The family on this occasion quickly pass through the town, out into the peaceful rural safety of Grandpa's house. Inevitably of course you know Trouble will probably come even here, which it does later in the film.
Grandpa's house isn't as creepy as the creepy elements of the Boardwalk, but it is quite eccentric with all the sculptures, stuffed animals and whatnot, and our first sight of him is him lying on the porch, suspected to be dead. So again within seconds the comfort and safety of the place are compromised. I'm not an expert on North American English but Grandpa seems to have a sort of 19th century accent, marking him and 'his world' apart from the general modern one. As something quaint/primitive/exotic/possibly unsafe. He doesn't have a TV, which dismays the boys and obviously accentuates the isolation from the familiar.
Concert Scene
Once again we fly in low over the boardwalk in the evening. The atmosphere is much more adult than the daytime, with the burning barrels, sax guy, concert and Michael catching sight of Star. There are still some younger teens about though.
Lucy Walking
Lucy is walking around the outskirts of the Boardwalk where it is quiet. She sees presumably the wife of the security guard putting up his missing poster, who turns and gives her a sad wide-eyed look, causing Lucy to turn away abruptly and slightly shaken.
The Vampires, Lucy and a literal lost boy enter the video shop. The boy is almost immediately found by his mother, and he and Lucy recieve lollipops, but the Vampires doing a brief tour around the shop and being told to leave as they are banned etc confounds the pleasant and relaxing resolution with an element of menace. The roar of their motorbikes is in stark contrast to the otherwise quiet ambience.
Boys Pursue Star
Michael and Sam pass through a circusy area with giant, slightly grotesque/disturbing papier-mâché heads on display. It is crowded and jostly and loud 'funhouse' music is playing on a Hammond Organ or whatever.
Sam 'escapes' from this area into the comic shop. Note there keep being adult/horror posters/magazines in the periphery of the shot - the Sampson electricity machine (reminiscent of Frankenstein and hinting at sexual prowess), the 'shoot your kids' line on the video magazine, some kind of weird moving mannequin or whatever that is in the other room in the background etc. As well as many missing people posters.
Sam is triangulated by the other boys, causing a few moments of alarm, and begins to be weighed up as cool or not. The 15 minutes ends during this, but if we had've gone to 15:40 we would see some rowdy punks causing a disturbance, then stealing comics, and the comic shop boys assessing Sam as worthy and insisting he take a vampire comic as it could save his life.
Summary
Obviously familiar tropes
Rites of Passage/Transition to Adulthood
Ordinary people being forced on Heroes' Journeys by unlikely circumstances
Evil entities which look human but aren't and are going around pretending to be human, but working against humans
Only a select few know about them, the public in general don't know and can not be persuaded
Ordinary person accepted into this group
Moving from comfortable, safe homeland (Phoenix) to a colourful, strange and less safe foreign area, with a 'Wizard' figure instigating the move. Idk exactly what verb to use for it, instigating isn't exactly right. An entity which moves people from the World of the Living to the World of the Dead is called a psychopomp, and I expect there's a name for this kind of wizard-world-transition figure but I haven't studied this kind of thing and don't know it.
This 'creepy clown' aesthetic combining comical and horrific elements - I've never seen the juxtaposition explained or why it is so affecting, except that back in primitive societies our ancestors had shamans who would do sometimes comical, transgressive behaviours in perfomances for some reason. Sometimes with scary masks and outlandish costumes. This was a long time ago for White people and idk how much lore of that has been recorded. Apparently the court jester sort of descended from that role. He was able to mock and contradict the king by occupying a comical role and relieve tension in that manner. This is one of those things I've never been able to find a book about - another being the White Hart, which also descends from prehistoric days and appears often in pop culture.
Anyway the combination of the childish/happy/party elements with the menacing/unsettling/scary ones creates an arousing yet tense atmosphere. There's obviously something about a (partially) hidden threat which freaks us out more than just an open one, which is why stories tend to be structured the way they are. Existential threat imperfectly concealed by party/holiday outfittings fits that. Also similar to Jaws I suppose. In a theme park you are in a sort of parallel world for a start. An immersive and stimulating environment. Secondly it's now dark, which jars with 'theme park'. The characters become really adrift in this new 'land', with allies (comic shop boys and video shop owner) and future enemies, as yet only on the periphery, established.
I think the 80s cultural motifs fit this premise well. Bikers/goths/metal/punk/New Romantic etc. It wouldn't work as well in say, the 2010s I don't think. The Lost Boys really does a great job, in its first quarter-hour, of transporting us in from normality, over the sea/across the country to this new outlandish Place with good and bad characters, and drawing the lines for the separation-ordeal-victory-return action to come. Even Michael's corruption/fall into half-vampire status is sort of foreshadowed in his 'bewitched' pursuit of Star, while Sam splits off.
What films would you say has a stronger first 15 minutes?