I don't think the mangaka plays games herself cause there are some things that seem off like how the PC broke lol. Ignoring that tho, it's a pretty cute story.
If Ruri was older it'd be strange. But she's like 12 so her suddenly liking the MC is pretty believable to me. When I was 12 I went from dislike to fondness with older relatives/friends pretty quick, for the most random of reasons.
@sdarkpaladin I mean is that really so strange? I play games all the time. But I still try to go to bed by 10 pm usually. There are some days where I sleep late but usually not. The earlier you sleep the earlier you can wake up.