Thanks Ben for your great insight.
You are right about the clash of chords, I did it on purpose to make it sound more "desperate and dark" like the sound that is creeping around, there are few more points in this song where I used it. But since your reaction showed me it's noticable and it bothered you, I might change it to straight chord after all.
You are also right about the melody, I've tried a different approach - used the same chords with a little variation, but changing main part of melody or "theme".
This whole thing should lead to the last part and main theme with two cellos. But now you mentioned it, I agree there could be more of it trough song.
Anyway, thanks a lot, your insight is well appreciated :).