It's highly likeable and I galloped through it.
Its Skeleton Knight (called Arc) is lovely, because he's such a big kid and he gets so excited about fantasy stuff. His first orc! A flock of wyverns! Visiting an elf village! Everything thrills him and his friends soon realise that he'll geek out over things that, to them, are completely normal. He's a gamer who found himself in his game character's body, which means he's got game-breaking strength and off-the-charts spells... but he's still not invincible. A clever enemy can simply dodge his attacks. He's also capable of getting over-excited and bringing comedy mishaps upon himself.
He made me laugh. He's a thoroughly nice chap, although he does love taking the bad guys' treasure after defeating them. He doesn't always kill the guards he fights. He might just knock them unconscious, depending on whether they're just ordinary blokes doing a job or actively participating in villainy.
As for that villainy, that's surprisingly nasty for a show with such a jolly, overpowered hero. This world contains kidnapping, slavery (including children), royal assassination, gang rape and more. Crunchyroll put a viewer warning on some of the early episodes. ("This show contains scenes that some viewers may find disturbing. Viewer discretion is advised.") That's the rapey scenes. The would-be rapists we meet are always foiled just in time and never do the actual deed, but there's still no doubt about the level of women's rights in this pseudo-medieval world. Meanwhile, elves and beastmen (including children) are being kidnapped for the slave trade and sometimes get stabbed in the leg for fun. Sick or injured ones aren't worth selling, so they just get executed. A prostitute gets pushed into a monster's pit and eaten.
There's also politics. The royal families and nobility of various countries are liable to plot against each other, order assassinations, violate treaties and/or help run that slave trade. Even the apparently nice ones might end up negotiating support for their bid to prevent a sibling from taking the throne. Can we trust her? I'd have taken that gamble, personally, but the elves might still be putting their heads into the noose of a Game of Thrones.
Given all that, what looked like a logic flaw could be regarded as characterisation of this unequal society. Everyone assumes that Arc is human, even though he's a seven-foot-tall skeleton who's completely hidden inside head-to-foot armour. The only person in these episodes who could match him physically is Goemon the beastman. Why should everyone assume he's human? Answer: it's a status thing. Humans have all the power and wealth, so only a human could afford that flashy armour.
Despite all that, though, the show's basically fun. Arc's a goofy nerd who always does good and has ridiculous power levels to back that up. He makes likeable allies who aren't overshadowed by him at all. (Ariane, Chiyome, Goemon, etc. are all no less important than him in their rescue operations.)
I enjoyed this show. It's still a light novel adaptation, so for instance Ariane's secondary plot function is to have big boobs. (But she's an elf! Surely elves should be slender?) The villains are depraved (and I'm hoping for a Season 2 because the big bad's still out there), but you're never in any doubt that Arc and his friends will triumph. Nonetheless, the show works. It's fun and funny. I'd recommend it.