Wow, you're pretty serious about ramen!

Here are a few corrections:

Ramen Restaurant Nearby

Finally, I completed all 3 flavors in a Japanese ramen restaurant, which just recently opened. They did a special promotion until yesterday that offered a bowl of ramen for only $5 that included tax.

that included tax = including OR tax included

Since it's located nearby my home and I used to be a ramen freak years ago, I thought that I would be its regular customer, if it was good.

nearby = near my home OR nearby. (with 'nearby' the fact it's near your home is strongly suggested anyway).

After tasting 3 of the main flavors that they offer for now, I judged that this ramen restaurant would be able to compete with others in the future, but not for now. I mean it's potentially okay as a new ramen restaurant, but I can see its room for growth. Especially, for noodles. I want to find the ingenuity in the noodles, something elaborated.

but I can see its room for growth = and I can see it has room for growth (and works better here because room for growth would be considered something good - like being potentially okay).

Well, but it's okay, if it's promoted. It's worth paying more than $5.

It's okay = It could be okay (it seems like this is your prediction for the place, so could be shows you hope it will become okay).

Well, these are some pretty minor corrections. Overall it reads rather well and the meaning is very clear. Good job!