Great series, we really need more concise romances like this. More than oneshot, less than a hundred-chapter epic.
One thing I'd change with this ending's translation is that after the merge, she's not repeatedly saying "Koaki" and "Chiaki", she's just saying "me" or "I". Honestly I think I'd prefer that being preserved; it just seems funnier saying stuff like "You make me like you this much, then say you'll let me win!?" or "Even if I forgive you, I won't!" There's just something entertaining yet endearing about her talking about both sides as herself, simultaneously recognizing that there's two sides in her and that they're both undeniably her.