Supplemental material: www.swahilipod101.com
I just signed up for this. there is a LOT of material that i think would be helpful.
PS: I am not affiliated. I just stumbled across. there is a 7 day free trial
Yes! I came across this on Youtube while looking for listening comprehension exercises and was going to post about it eventually but you already got there!
The listening comprehension exercises alone are enough to recommend it, especially as Duo isn't as strong in that area as reading and writing. When I have a bit more time on my hands, I will go through them in great detail.
Check out their Youtube channel, where they have some of their resources for free too.