From past experience I find the majority of the trap in game anime to short anime with mediocre entertainment value and storyline. Characters tend to be poorly put together or random NPCs that don't matter. Half the time the storyline does not even make sense in these type of anime but Overlord is fantastic and one of my favorite.
I found Overlord to be a binge watch anime that I can't get enough of. Amazing action scenes with a overpowered main character with frighting powers. His name is Ainz Ooal Gown and I have not been able to decide if he is a good guy hero type or a ruthless dictator bad guy. His companions tend to sway both ways as well which makes predicting what happens impossible.
Just like any good anime it has the perfect amount of pervertedness and a ton of humor. The storyline is great and will keep you in suspense just long enough to have you on the edge of your seat. Even the scenes that are not plot fulfilling tend to be very entertaining and a no point was I bored.
I wish I could of gave this anime 10 stars but while it's perfect for what it is, it's just not quite a masterpiece but equally entertaining.