Can't wait to try it on iOS because I love idle-growth apps like this. Might be worth looking into how Sleeptown/Forest implement features you're interested in.
That's a really well designed app, thanks for sharing. I really like their bedtime reinforcement mechanism. Sleep town seems to be much more focused on the scheduling aspect of sleep and reinforcing strict routines whereas at the moment Nebula is much more focused on going after the snooze button, but both of these things are quite related.