Congratulations on the release of Cafe Memoria!
I had so much fun playing this game; even though it's short, the structure worked perfectly for the story you were trying to tell. I enjoyed meeting all of the girls (especially the ones who weren't in the demo), and I felt like each of them had their own unique personality. None of them felt too much like a stereotypical "shy girl" or "tsundere". Exploring the different food and drink choices was also fun.
At first, I wasn't too sure about having to play the routes in order, but once the chronology was set up it made a lot of sense. The set order works well in allowing the player to spend time with each girl, while gradually allowing the girls to build off of one another in their interactions. It helps that the routes were short and sweet so I never got bored with one girl. Also, the unlockable extra art was an awesome touch which I really appreciated.
As for the plot,
I was quite happy about the reveal with Julia, especially since it was built up over the course of the other routes. It's pretty predictable for games like this to leave the romance open at the end or lean towards a "harem ending," so the twist was really refreshing. I feel like Cafe Memoria never sacrificed its characters' personalities in an attempt to shoehorn in romance. And, giving Ryne someone whom he already liked made him a more well-rounded and realistic character in my mind.
Also, Julia is best girl so I was not disappointed. ^_^
Props to the relatively high production value of this free game, especially with regards to the character art and the voice acting. The menu choices and rating system were also really neat.
Like others have said, I would definitely love to see a longer sequel to Cafe Memoria that digs deeper into each of the girls' routes. I could see it selling commercially (I would buy it), and this game is a great way to pull in people's interest.
Constructive criticism: I wasn't too sure how to feel about Ryne. He's obviously a nice guy and the girls repeatedly say it about him, which means there's a danger of him being too perfect or just... unrealistically likeable? Then again, I appreciated the times when he got annoyed or didn't get along with the girls. I felt that he was more developed as the game went on. If you do make a sequel, I'd love to see more of Ryne's personality and internal conflict.