I managed to find the time to play through this last night - I have to say, I'm pretty impressed! It probably helps that it hits many of my favourite story notes (both from within SciFi and without), but it's nicely put together, has a great sense of place and some engaging characters.
If I were to offer criticism, the main thing would be that the 'first act' is over too quickly, and mostly consists of the player messing around in various places looking for things to do, and I kind of suspect that the game could fail to get anywhere at all if the player doesn't bother to reply to Emilia's poetry post. It felt a bit to me like the plot was missing a driver, like there should have been something drawing the player into the world of BBSes other than straight curiosity; perhaps an odd problem with their computer they need to ask for help with, maybe a broken piece of software or something, which could have had them exploring with a bit more of a purpose... and also could have potentially served as a mediator on the speed of the protagonist and Emilia's whirlwind relationship, which in my playthrough I think whipped up in the space of about 45 seconds.
The choice to absorb the player's identity for the protagonist and not have any monologue or narration was for the most part very nicely executed, IMO, and added to the immersion of the environment. My one complaint in that regard would be that - while I can understand why the player's messages were not shown to the player for purposes such as projection and avoiding breaking suspension of disbelief - it seemed a little disembodied to hit the 'reply' button and instantly have written and sent a message. The first couple of times I did it, I wondered if something had broken or whether a reply had actually been sent, and I'd guess that a short key-tapping SFX and a pause would probably have helped.
And it's a good thing that my day job has prepared me for memorising and typing in long strings of numbers! I tend to agree that while it added to the immersion the first few times, by the end of the game I was thinking "surely even in 1988 people were able to automate their modem diallers..."