They're both such great games. And there are a lot of other games that were made by fans too that are based on the same concepts. Basically the games are based on exploring the main character's dreams. .Flow is a fangame of Yume Nikki. Yume Nikki was the first one that started it all, but no one knows where the creator is and what became of him since 2008. Smile is a character that you can find in Sabitsuki(the main character of .flow)'s dreams. My favorite part of all the games is that the creator (usually) doesn't tell you why things happen in the dream and what symbolizes what. You have to sort of figure it out based upon theories made by fans or figure it out on your own. I bet you'd really like Yume Nikki and .Flow!