The story takes place in a D&D inspired world where battle between the good and the evil is commonplace. The main character has gone through a traumatic experience in his childhood because of the infamous goblins and has decided to dedicate his entire life to eradicate them. So it is all about how cunning the goblins are and how goblin slayer comes up with various methods to deal with them. As such it should be the only thing one should expect before watching the show. Otherwise they may get disappointed.
Even though the premise is simple, it doesn't get repetitive because the situations he finds himself in changes everytime and his methods change as well. There are several classes of goblins, and some of them are significantly powerful. It made matters more challenging for goblin slayer and his party. So I was pretty much entertained throughout.
Many people say that goblin slayer has plot armor. Well what do you expect? The name of the show is Goblin Slayer after all! Just like Naruto, Ao no exorcist, Mob psycho 100 etc. Having plot armor and being overpowered are entirely different things. Having plot armor is not a bad thing. Being consistently overpowered may become a problem because sometimes such a story becomes unbelievable. But GS is not overpowered and he struggles to kill the goblins. He uses unconventional methods to kill them. That is the strength of the show.
The characters are clearly the weakest part of the anime. They are all one dimensional and are only there to help goblin slayer. However, while I would have loved to see some backstory for each character, it doesn't matter as the story is only about GS. Only character to grow over time is Goblin Slayer himself. He initially keeps everyone at a distance and only obsessively cares about goblins. The fact that we can't see his expressions due to the ever present helmet doesn't help either. But by the end of this season, he has slowly changed a bit and is slightly more sociable. I don't know how much more he develops beyond the storyline adapted in the anime. But for 12 episodes, that is a decent progress.
The animation is above average. Sometimes there is use of CGI while goblin slayer walks. It is unnecessary and looks weird. The action scenes are decent. One thing I disliked is the mild unnecessary fanservice. It is not omnipresent throughout the entire show, but the way it is done (with weird physics, unnatural clothes etc) breaks the immersion in the story.
The opening song done by Mili is very good and makes the anime feel like some dark fantasy. It is a shame that it is not really a dark fantasy however. The ED is a bit bland and is not to my liking. The rest of the soundtrack doesn't stand out much either.
TL;DR - Goblin Slayer is a decent anime. It is neither one of the best, nor one of the worst shows out there. It is quite enjoyable if you know what to expect from it.
