Short little VN here. I think the concept is neat and it's written well enough, but a little more could've been done with it. Letty kinda just does the same things that Reimu and Marisa and Sakuya did. Might've been more fun if she encountered other characters instead of Chen and Alice, or if she did something special with the spring instead of just returning it like normal.
I like the art and music quite a bit, and the characters' faces were charming to me (like this one)
In short, 'twas cool.