I really enjoyed this in spite of the missing assets. I think the biggest issue you had was trying to write the ending towards something longer with more chapters to come outright, instead of having it be a "standalone with sequel potential".

I think you're well aware of Isekai tropes, which makes you suited to write a clean story about them, and the interpersonal relationships reflected felt real. I enjoyed your twist on the conventional isekai setup in that it was a two-way sort of passage, and as a reflection of immigration more than anything else, closer to the anime series Gate (albeit without those more unscrupulous bits that they refused to think otherwise about).

I think if the visuals got cleaned up and the scope was adjusted to that standalone premise, this could be a very nice short VN that anyone can pick up, put down, and feel satisfied about.

Good work overall.