First line: I can wipe out the heavens, the earth, and the air in seconds.
Second line: I can nerf your power, your brains, and the protagonist.
Protagonist: Hey, hey, Author, what kind of abilities do I have? The protagonists in other books are all super strong! Either they have a System backing them up or they stumble upon some amazing opportunity. At the very least, they're all geniuses with extraordinary talent.
Author: You start off with amnesia, and you're a little brain-damaged on top of that.
Protagonist: ??? Are you an idiot or something? Who treats the protagonist like this?
Author: Get lost! Keep yapping and I'll turn you into a girl and toss you in as a magical girl.
Some time later...
Protagonist: Wow, I'm so strong. I can stroll through hordes of zombies, and with girls keeping me company, it's practically a vacation!
Author (coldly): Is that so? Let's see how you like this nerf.
Protagonist: Oh, this nerf isn't so bad. I can still hack through a zombie or two with ease.
Author: Then here's another nerf.
Protagonist: Whoa! Come on, man. You've nerfed me so badly I can't even pick up a weapon.
In short, this is an ordinary crossover novel.