The first thing that pops out about this anime is the art style. The art style uses a beautifully water-color palette for the backgrounds. Honestly, it was the attractive art style that intrigued me to even start watching this anime.
This anime rolls at a very slow pace. For some, this may seem like a bad thing, but for me, I generally like a story told at a slower pace with a bigger payoff. The slow pace allowed for strong character development and a true feeling for the world these character reside.
The interesting thing about this anime is that we, as viewers, still don't know what truly is going on. It appears the characters are in some sort of virtual reality world, but unlike Sword Art Online, the characters are completely unaware. This adds a compelling theme to the story because we're not sure how serious the implications of their actions are. For example, is a character death in "that" world a true death? Can they be resurrected? Or do they wake up in some sort of Animus type device?
With that, I would definitely recommend this anime, especially if you prefer slow paced stories and are looking for a time killer. The animation style is gorgeous, characters are adequately developed, and the story is rather intriguing.