I'm flabbergasted. This show is wack, in a good way. I don't think It's perfect, but even so, it's so weird and original I can forego its faults. Do you think you know where the story is going? Think again. Before you know it, everything has changed. It's also a brilliant use of the isekai genre. I've seen way too many isekais and at the end of the day they start blending together, few stand apart. But this one, I've not seen anything remotely similar. But the main flaw in my opinion has to be its lack of momentum, there's great build-up until it gets partially reset. It's irritating. Its characters, though surprisingly well developed can be annoying especially the main character.
Simply put I think it's so original that it's a must-watch. It also has a really good ending. Nicely wrapping things up, leaving room for a second season without a need for one.