Feyfall

Built in Ren'Py, Feyfall by Obsidian Rose is a visual novel that is ongoing. Expect fantasy, transformation and monster girl with 2D art. The current build is 0.1 (1 GB). Available for Windows, Mac, Linux and Android.

From the box: “What is the Winx series known for? Ordinary girls with fashion-sense turned into glamorous fairies with each of their themes. Often with skimpy clothes.”