@Rodrigez89 if you think the art is merely above average than your standards are broken, or you’re comparing top 10 mangas with overload, we don’t use mangas like Sun ken rock or one punch for art quality comparisons.
As far as skills go they exist, not in AAA rpgs but in the old K/J-MMORPG era (especially the 10m long buff combo casting thing) are all(most*) real and existed back then, the writer is basically using old forgotten games as a source as in many aspects of Overlord game mirrors Ragnarok online for example.
And calling ainz overpowered is wrong, he’s just fighting people that are ignorant about his gimmick class, to defeat ainz you just need a Death null and auto revive, which are easy to come by for people in his rank, he’s a semi powerful class thrown in a newbi area. Oh and he definitely can’t touch an end boss due to them usually having a death null.