How Did Anyone Beat This In The Arcade?

The same way you beat any game in the 1980s and early '90s: lots of pattern memorization based on trial and error. In the arcade, that means lots of quarters.

Once a game like Dragon's Lair was memorized, you could play through the entire thing on only a couple quarters, to the astonishment of arcade bystanders.

Kids and teenagers had more time back then because smart phones and Instagram and YouTube didn't exist. People underestimate what a huge time sink those can be.

No one had Internet access. You could play a game, play an instrument, read a book, go to the mall and the arcade and maybe catch a movie, go outside, or watch whatever happened to be on the 3-4 network TV channels (or possibly cable if your family had the money). And TV back then was mostly terrible.

So if you had $10 in your pocket, that was an entire afternoon of entertainment at the arcade and movie theater.

If you had it down you could beat Dragon's Lair (and Space Ace, and the other Laserdisc games) with a single credit. IIRC there is no randomization within each scene; the only element of randomness was which out of a set of three scenes could play stemming from completing the previous scene. Once you've seen them all they always play out the same way. Further, each scene is only played once per complete game.
I grew up in that era.

I probably dedicated 1000 hours playing the same 4-5 NES games.

I remember playing the original Zelda with self-impose challenges like get hit and start over. I had so much time to kill.
Crazy to think that $10 in 1980 is $40 now
- Back when people were making a buck or two an hour though
As a child in the 90s, I remember Saturday and Sunday afternoons being incredibly boring if we didn’t go out. TV was shit (still is), and on rainy afternoons you were basically locked at home.

By the late 90s, at age 10, with no internet access in my county, I was mapping ways to beat the Water Temple in Ocarina of Time. I remember scheming for hours, using Farore’s Wind to take me to the beginning of the dungeon and jumping to the platform on the 2nd floor. This way, I was not using the only key I had on the middle pillar, which is what almost everyone got stuck on.

But yeah, I remember the tail-end of this at that time and starting a whole new game to try this out. And it worked. Still proud of 10 year old me. It’s interesting but I hadn’t felt boredom in a really long time.

It wasn’t that hard if you kept feeding it quarters. It took a lot of trial and error, but having infinite lives means it was eventually beatable.

This is the real answer. Arcade games weren't made to be beaten, they are made to extract maximum quarters. Most of these games don't even have a real "ending", and why would the devs bother? They already got your money.
- It wasn't a case of "why bother," it was a case of evolution.
  
  The original intent of arcade video games was to obtain a high score. You played until you died, and the game progressively got harder until you choked, or it hit some arbitrary limit of difficulty and went on forever, or in some infamous cases (Pacman) crashed. These video games were a conceptual extension of the arcade games that existed before: Pinball machines. Pinball games don't have an end state, you play indefinitely for a high score until you choke.
  
  Arcade video games could have endings, and even though in the very early days they didn't: Crystal Castles was probably the first, in 1983. Even then, after reaching the "end" the game would loop so you could play it indefinitely until you died. Because that's how arcade games worked. A lot of games starting from the 1990's and beyond had endings of some description or another because they were in some way narrative based. In most cases (with the exception of some 1 on 1 fighters) you can still play another loop after the ending.
- Arcade games weren’t made to be beaten

you try to not play any arcade if you haven't seen anyone else play first, that cost you money :) My experience with Dragons Lair is that it was a nice game to watch, and a bad game to play, it was expensive and as someone else said in the thread it requires you to memorize the movements, it was never random

Quick time events are such a garbage game design concept
- As an interactive method of storytelling, I think they're fine (but not my thing). I think the problems really emerge when you try to combine them with the revenue-driving elements of an arcade machine - the challenges need to be designed to kill you so you'll keep paying rather than giving you choice or staking you in to the story further.

I assume lots of trial and error and following guides from magazines and such. Games like Dragon's Lair aren't really meant to be that winnable, they're just designed to get you to buy as many coins as possible to keep trying.

I remember watching a guy play an arcade game back in about 1990, I think it was spy hunter or something but the car could do a jump and side scrolled to the right. Not sure. Anyways, over the course of about 4 hours this guy plunked about $100 worth of quarters into the machine until he beat it.

10-year-old me was, uh, impressed to say the least. I tried playing it but I only had two quarters and lasted less than 3 minutes.

Those were the days
Definitely not Spy Hunter as that game loops and has no ending.

I remember using a cheat on the home computer version for my ZX Spectrum for infinite lives. I got bored after a while because of the fact it never got anywhere, just scenery changes every so often.

There was a remaster that was put out a few years ago: steam, gog. It was a nice piece of nostalgia finding it. From playing it on arcade difficulty and comparing it against the easier settings, it was pretty obvious this game was meant to suck up quarters. You just had to have everything memorized.

The mechanics of that game were more like a very fast choose your own adventure than the traditional move joystick left, spaceship go left mechanics.

Because the graphics were coming off a laser disk, they didn't generate on the spot. There were predetermined outcomes to every move.

When people figured this out, information started to collect in the magazines, and the game became beatable.

This is correct. I remember getting patterns from a magazine.

Also, there are flashes on-screen that could guide you if you are quick enough.

ETA: Just watched a walkthrough of this game. I've never seen the ending before today! I'm certain horny teenager me would have just loved to see the princess's huge nipples.

My older brother's friend worked at an arcade. He opened up the panel and loaded this game up with credits for me. I still never got close to beating it

It's simple: they didn't.

The only arcade that had that game charge $2 or something like that for each credit. I tried it once and then never again.

It was 50 cents per play at launch.

I (my mom) spent so much money on this game. It was in the laundromat near our home. My little brother and I would die so early on. Back then it took some time to figure what was going on with this game and what to do. We were so young so that's all I recall.