This app was mentioned in 3 comments, with an average of 1.33 upvotes
Thanks for the recommendation! I'll check Habit Streak out, it looks like it would be good. For me, a heatmap is a "nice to have" rather than a "must-have," but it would definitely be huge improvement to the app. Maybe I should try and make my own application for it sometime.
I use Habit Streak (Android) and it just gets the job done.