I see the question all the time about films, such as the new pile-of-arse Resident Evil film (imagine me saying that scornfully, if you will). Apparently super-mega-awesome-hot-etc Alice loads quarters into a 12-Guage and fires it. Someone on a forum rightly questioned this, and was shouted down in this manner;
"LOL theRS zomBIEs and lickerS And stuff ANd yoR asking THAT lol!"
Yes, there are zombies, lickers, executioners. There are giant monsters that sprout from a single body, because they have a parasite (that can apparently create something from nothing). Do I care? No, because within its world, that's what happens. If such things existed, that's how they'd act, but they don't. Shotguns exist, as do quarters. They've not been created specifically for the story.
I guess that's the distinction I draw, if something is from someone's imagination, go absolutely nuts. Dwarfs, magic, lightsabers, Codecs, clones, genetic memory from a transplanted hand (oh Metal Gear.. How little sense you make) are all fine, because they're a part of a whole.
However when you have a work of fantasy, and start dicking about with things that don't make sense (innovative fantasy as opposed to corruption of established reality) that's when it starts to get ridiculous.