As you probably read from the other reviews, the writing quality does get better. Just power through it and you'll get to the really good parts.
There are a few things that came to my attention though. The first would be the terrible synopsis you have written. I mean seriously, you get no information out of this.
And
Please
Put
More
Words
In
Each
Line
Anyway, the story is pretty interesting. A dude who gets reincarnated into Tensura and gets OP real fast is always a good combination in my books. He also goes into other universes too. (Danmachi, highschool of the dead and Campione or whatever it's called)
The MC is a crazy and cold blooded killer, so be aware of that. Being calm and nonchalant when committing genocide kind of crazy, to be specific. I like it but some don't. To each their own I guess.
Just give it a try if you're interested and don't get discouraged by the worse grammar in the first few chapters, trust me it truly gets better.