In Spelunky, aside from finding the rare crates, the only way to get items is by giving blood sacrifices, which eventually also gives you an item which raises heath for collecting blood, or by buying them from the shop owners. The shop owners have a lot of items, they can pack a lot of damage and the sacrificial altars always seem to have fresh blood on them. Now put two and two together.
On the other hand, the sacrificial altars are not that picky about who gets put on them, so egregiously-territorial cavemen, hostile cultists, man-eating plants, and marauding yeti can be sacrificed for profit. For all we know, the whole reason that your character can survive at all is because of these brave entrepreneurs. And you'll probably try to kill him to take his stuff.You Bastard!.
It could even explain why they're so quick to kill you for even the most accidental of slights, malicious in intent or not. They've seen adventurers come and go hundreds of times; who knows how many times one of those opportunistic little bastards (You?) have tried to steal something (or worse) from them? It's only natural that, in time, their trigger fingers would get a little jumpy...
The little enemies like bats and snakes and other such things aren't really disturbing until you realize that they're THE SIZE OF YOU! Cobras are the worst seeing that they spit out giant wads of poison everywhere.
This is less terrifying in the remake as some enemies become scaled down a bit with the new art.
The existence of the kissing parlors border on this. Not only do the damsels taken from these places respond in the same way as the more-explicitly-distressed damsels, implying that they're not too happy with their careers, there's the response the shopkeeper has if you attack her (via whipping): "Hey, only I can do that!". (Well, in the original, at least.) To say nothing of the fact that the shopkeeper is entirely willing to sell the damsel to you. Sounds like a legitimate business.
Whilst it is vaguely logical that the value of loot rises as you go deeper into the caves, answer me this — why is a single gold bar worth $500, but a stack of THREE gold bars only worth $1000?
This is addressed in the Xbox Live Arcade remake of the game, where a stack of three gold bars is now worth $1500. If you whip the stack, you'll see why — it's actually three individual gold bars arranged in a pile. Clever!
Another thing worth noting: In the remake, if you pick up the stack, it's recognized in the after-stage loot as a stack, while whipping it makes each one count individually. Of course, they're worth the same amount of money either way.
Ana's spaceship is vaguely egg-shaped. This may seem just like a wacky design for the sake of it, but there's actually something quite fitting. The story is effectively, in a way, about how Ana and her gang grow as adventurers to save her parents; in a way, Ana is "hatching" and coming into her own as an adventurer. Not to mention, the True Final Boss in the Sunken City is Hundun... Which, in this game, is the world egg.
