I like this slight change

This is getting interesting, keep up the good work.

In the Webcomic they did have Tatsumaki fight Saitama and in her weakened state, Tatsumaki was able to lift Saitama roughy a meter or so above the gro7nd before the intense concentration required to do so reopened her wounds from her fight with the self-named God level threat she fought earlier (I won’t say his/her/its name because spoilers, but I will give you this - he/she/it would DEFINITELY destroy Boros in a fight). I would suggest being careful when it comes to fan fiction - there are people without lives like me everywhere, and there is always someone who will shout “That’s not right! I bet you only casually watch anime!”
Oh, and be careful to not make Saitama OC. He’s a simple, nice guy, I’ll give him that, but I feel the need to mention one thing that will hopefully destroy any chance of him acting like a Gary Stu (personality wise, that is. He’s already OP AF). One time, a man was about to commit suicide. Saitama said he didn’t care if he jumped, because it was what the dude wanted and it didn’t affect him.

I personally think that Tatsumaki could have easily destroyed Vaccine Man. So far, Tatsumaki has never had trouble taking down any Demon level threats (with the exception of that one time she tried taking on multiple by herself, while having her abilities weakened by another ESPer) and I don’t think that Vaccine Man would have been any exception. Plus, Tatsumaki was way too nice to Saitama. Every time I’ve ever seen Tatsumaki, no matter the situation, and even when losing, she still refuses to acknowledge any help she may have received if she had let others help. Otherwise, this seems cool. Keep it up with the good stuff.

An issue I've seen in many aspiring authors on this site is when they attempt 4th wall breaks in an attempt at humor, by addressing the audience. This can be done well, and it can be done very, very badly. The fact that you used it to display a character's thoughts by interrupting the story, when you could be using that space to explain the character's revalations in a subtler or tongue-in-cheek kinda way. Using parentheses never ends well, keep this in mind, it is very jarring a majority of the time and should only be used when the reader is aware of them and their use beforehand or is specific situations where it'd make sense reading about it.

The way you also tell the audience about things going on in the story at an attempt at humor is also very, very jarring and breaks immersion completely. In my honest opinion, the story would be so much better if the text speaks for itself without witty attempts at describing the opinion via the use of directly speaking to the reader.

Anyway, it's been a good read so far and is pretty damn good when you get past the rough parts. I suggest listening to any criticism thrown your way and adjust future chapters based on their feedback and your personal vision.

Get rid of the parentheses tho, they're gross

You have my complete attentionI honestly can't wait to find out what you mean by a tad different and how you'll do for your first story Do you have some kind or schedule or will you just update once the chapter is finished ? Also how long do you plan your chapters to be? And last question, do you prefer answering the reviews by private message or in a dedicated part at the top/bottom of the next chapter ? Anyway, I have plenty of questions but I'm sure I'll get answers as the story goes on so I'll stop here I hope you have a good day, and I'm eager to read the next chappie !

When you say things are just a tad different, what do you mean? Because the two you mentioned (both of which are very good choices, by the way) don’t give much detail on what you are changing. Is it like if Genos focused more on skill than pure destructive power? Or if Sonic and Saitama never met? There’s a bunch that a small change could mean.