This is my first review on Anime Planet so it might not be that great.
Infinite Dendrogram is about a VRMMORPG game that was released and attracts it's audience by being a world of which you can "Be anything and do anything." There isn't really any storyline. The characters don't go on any real quests. There isn't even a typical Adventurer Guild you see in most Isekai. The plot feels rushed and there are some big issues with the way it's presented.
Character development is ok, though it would have been a lot nicer if this had 24-32 episodes to have better backstory and flesh out the plot instead of compacting it down into 13. There doesn't seem to be much point in the appearance of some characters and there are some cheezy punchlines. It would have been nicer if there was more information about the game system, skill lists, abillities, items, etc. But there isn't anything there. The main character only has a few skills and yet he is level 41 at the end of the season? If that's the case, this wouldn't be a very good game in real life.