Robots existed back then, though most could easily be destroyed with lightning magic.

Has anyone mentioned yet that rats and spiders used to drop gold coins? It's unfortunate they don't anymore.

Dragons were able to go almost anywhere (even going through walls); the only reason they didn't run rampant is that the organizers of the race put up magical barriers that can stop even dragons.

Some slimes were made of metal, and such slimes were surprisingly agile, being able to slip away faster than one can blink. Those slimes could survive even nuclear explosions, but were cowards for some reason.

Back in medieval times, robots were more advanced and intelligent than they are today.

There's this old story of one farmer, who had some sort of chainsaw, managed to kill a god with it; yet that same chainsaw didn't seem to work for actually cutting down trees. (Actually, maybe it worked on the hardiest of trees, but not on the more fragile types.)

With a simple prayer, a bishop could give somebody the knowledge and wealth that would normally take more than a lifetime to acquire; even better, the bishop doesn't have to have said knowledge and wealth herself.

There was a time when everybody was male; even wives and princesses were male. Then, something happened, and about half the people became female.

A different story tells the reverse; there was an Avatar who was said, by many, to be female, bit all of the sudden, was somehow forced to be male.

(Note that the last two facts don't involve gender transition; rather, they are references to game series that add or take away the option to play female characters in later installments (Bard's Tale and Ultima if you're wondering what I was thinking of).)

You forgot swarms of insects as well. How a swarm of flies can carry around a pile of gold or a weapon I have no clue.

Of course, I suppose they could if they were African flies.

You could get away with crime as there were no Sherlock Holmes detectives, surveillance cameras back then.

A woman could make her husband raise another man's child and the husband would never find out as there were no DNA tests back then.

If your rebel teenage daughter came to you and demanded money and wanted to go do a slutwalk....you could slap the hell out of her. And you won't end up in jail for that.

Your wife could not threaten you with divorce if you didn't get her a thousand dollar diamond ring.

Let me tell you about medieval engineers: they were amazing!

Civil engineers could build anything! Tall towers on the top of mountains that was not affected by the wind and had perfect structural integrity; dungeons that went down, down, down into a large pool of lava (they could dig through everything! Large halls upon large halls with no need for reinforcements or columns! Of course, architecture was not a thing back then, so things looked a bit mazely. Going from point A to point B you often had to go through the entire floor. But boy, could those guys build!

Mechanical engineers were also great! Those traps you could find? That was their thing. They worked on security. They built very reliable mechanisms that had very long warranties. Those large massive doors that cannot be destroyed? Yea, they clearly weighted a ton. But push a button or pull a small lever and, presto! they open on their own (sideways or downwards). You know those windlasses and cranks and pulleys? Those were the cheap stuff, no security whatsoever. Great constructions had a switch or lever across the floor (see above) that you operated to open the really important doors. I don't even know what they used as a power source, but they were really reliable (unless some rock would be pressing down a certain floor tile or the lever would break). And the mechanism was very discreet.

I assume that you never went into an IKEA shop. One has to walk a serpent way through the whole shop over two floors to get from the entry to the checkout counter. They just want you to behold all the nice things they have...

I have, but only a few times. And I'm fairly sure there are more shortcuts than the ones they indicate (for staff).
In places where people live and work that philosophy would soon prove to be very impractical.

You just said it, the staff are the only ones who know about those extra shortcuts. You're not dungeon staff, you're running around killing dungeon staff, of course they're not going to tell you where the secret shortcuts are.

Yeah, sure, they'll put up signs saying "secret treasure room this way", but like the IKEA displays with nice-looking kitchens, offices, and bedrooms, they're fake treasure rooms with just a little treasure they can easily spare.

Thieves and muggers were generally idiots. They'd attack you if you were a lowly peasant. If however you were armed to the teeth and accompanied by 5 people just like you, they'd still think it's a very good idea to attack you with their rusty dagger in full confidence that they'd be able to rob you.

Weapons and armour made of steel were as cheap as a loaf of bread.

Actually, if you are highly experienced and armed to the teeth, every bandit you encounter will *also* be highly experienced and armed to the teeth.

Also, a couple other things I've learned:
* Glass is actually a rather durable material; a sword made of glass will take a long time to break.
* Glass is rather fragile; a sword made of glass will break on the first swing, but not after inflicting a lot of damage.

Also, a couple more:
* Being heavy makes you move faster; being tall does not.
* Being tall makes you move faster; being heavy does not.

I'm thinking TES: Oblivion here.

the rats were big. REALLY big.