I was recently going through and translating the filenames and descriptions for the PiyoPiyo set, and noticed that a couple of the songs' descriptions (including one which would eventually become "Plant" in Cave Story) made reference to a project known as "「愛している」と言ってやる", which translated in English would be something like Saying "I Love You".
○ Giraffe Girl: Opening theme for Saying "I Love You".
○ Love Scum: Main theme for Saying "I Love You".
○ The End: Ending theme for Saying "I Love You".
Doing a quick scan of the internet yielded no real results (at least as far as I could tell), and I also can't find this project mentioned anywhere else on the forums except for the threads that show the original descriptions for the PiyoPiyo set.
Does anyone else know anything about this project? Was it a game that Pixel was working on, or something else?
I can imagine they're just love songs he's wrote to his wife. I mean, if that's the case, they've definitely worked considering they had a child in August 8, 2004. Actually though, maybe that's why one of the songs for Yamashit Farm was used instead of the one used for Beta Cvae. He wanted a song dedicated to her in his game.
From what I heard, it was definitely popular in Japan when it released, and was a big influence on a lot of the cyberpunk media created in the 80's, although I'm not an expert on the subject. That being said, it may not be a reference to Blade Runner; Pixel used a lot of rain imagery and references to rain in his works back then, and I think it might be more of a reference to him getting lost in thought on a rainy day. That's just my interpretation, though.
EDIT: Besides Saying "I Love You", there is also early music for Doggy Wyvern in the files. Of them, "Broken Toy" seems to have been cut by the final version of the game, but "Flying on Air" / "Catching the Airstream" made it in as the daytime music. The song "Rain" was also repurposed as the ending theme for Doggy Wyvern, as well. However, both of these songs were altered slightly, and rearranged into the XG MIDI format that the final build of the game uses. The only song that was publicly released from this final build (as part of the OrgView package) was 冷たい水路, or "Freezing Waterway", which was the nighttime music.