What is the path of gaining popularity in matter of no time? By doing something extreme, of course. Goblin Slayer nailed with the first episode by exceeding in unnecessary amount of violence and gore, which disgusted some people not because tons of gore is a nasty thing, but because many parts had terrible action (usually two characters are fighting while others are waiting for their turn, or someone goes banzai and dies in an instant), awfully made protagonist and antagonists.
The story is cliche as it can be, generic fantasy world with names like kingdom of elves, they didn't even bother naming kingdoms (not mentioning nonexistent names of the characters), already seen and used races like dwarves, humans, elves, argonians... umm I mean lizards, etc. Races want to survive and of course evil creatures such as goblins and demons want to ruin everything, so they fight. There is adventurer's guild with a plenty of quests which offer rewards, though it looks like typical high school show - boasting jocks, an elite group which despises others, which wasn't necessary at all...
The characters don't have names. We know someone's race and age, bit of protagonist's past, and that's mostly it. The conversations are usually dull, it's either talk about how bad goblins are, pathetic bantering between the elf and the dwarf, or when the protagonist replies with one or two words to everything. The other problem with characters is such awful design (especially the voice) of goblins, not just that they look like someone with no imagination created them, they don't leave any impression of posing a threat with their pathetic figure and voice. Swiper from Dora the Explorer looks scarier than the goblins. Also, the logic about protagonist and his armour is ridiculous, but I guess he needs to look like a tough guy who doesn't talk much to leave cool impression. Never taking his armour off, even helmet, while helmets were worn only during the battle or duty as a guard, eating (not even removing his visor) and sleeping in armour and helmet looks more silly than cool and tough.
With all these flaws, it's not a terrible show. The first episode was a teaser that the show will be dark and full of gore and other nasty things, but it hasn't shown any more depth than that. Characters with no names, kingdoms with no names, even the dark theme started fading away with the annoying elf and the atmosphere is changing. Dark theme is getting thinner and the show is shifting into a forgettable seasonal anime with some adventure time and action, nothing more.
I guess there will be some demon master who summons evil creatures to take over the world and eliminate all the races or turn them into slaves, the protagonist will probably have another scroll to use as a trump card and poof, the end.