Just because it seemed not to hard, i spent the evening (actually about 2 hours) making a Spritz clone using kivy.
Code is a bit crude and all, but here it is for your enjoyment:
Here is an apk if you want to actually try it.
Only flat text files are supported, opening the option window is a bit slow (because of ColorPickers), but it’s functionnal, progression is saved, all the options i though were needed are there, and it seems usable.
You can find a lot of free book in the .txt format over at project gutenberg.