This would have been a very different, and frankly much better manga, if the MC knew he could take on a dragon because of his observational skills. That is, he's seen lots of different fights from the sidelines, and already knew all of the ways to fight the dragon, what its weaknesses are, attack patterns to watch out for, et cetera. Nope, instead he just figures, "lots of levels, lol" and dives right in with a weak weapon, and somehow bodies the dragon.
Do you think it will taste like a gator or like a cow?
"I don't know, it probably tastes kind of like wyvern."
"Wow, you've had wyvern?"
"Yeah."
"What's it taste like?"
"Chicken."
(Apologies to Denis Leary for stealing his joke)