Some tips: 1. You could use this widget with WP-super-cache, causer this widget is using JavaScript(jQuery). 2. When you change your Twitter screen_name(Twitter ID), or you change the Twitter ID you want to display, or you change the amount of the displaying tweets, you SHOULD delete the cache in WP-super-cache contents.
Any bugs, please contact me(zckevinzc@gmail.com), Thank you 🙂