Continuous scale is hard to explain to a user, and its meaning is somewhat lost an article of 3.5 VS 3 is not that much different. Instead focus on using a qualitative scale (but we still use the linear numbers to sort).
Add the source name as a small text, users might not know what the Icon means and this way they become familiar with the source. Maybe make it a URL that takes them to the source site.
Make the reading time an estimate of how long the reading session is. This value can be estimated using the existing data of users and it could be personalized based on user behaviour. We could also add a small penalty based on higher difficulties
Currently, the user might not understand what the numbers mean, especially in the mobile:
Maybe move it inside the preview in front of the time pass.