I didn't watch the whole video because it completely fails to describe the workflow. What I'm really interested in: how would Sprint.ly solve/represent this workflow:
1. Customer reports a defect
2. Programmer figures out there are two tasks that needs to be done by different people (in different places). One task depend on the other.
3. The first task is solved. How does the other person know to start?
4. The second task is re-assigned and then solved.
Actually, it doesn't have to be this complex. But at least have that in mind when showing your product; all todo-applications can tackle the easy stuff, it's when the more complex use-cases appear that most of them fall apart.
And when you say "make it possible for everyone to participate" I hear "no way to figure out what you need to do". Although it's good to have a place to see everything, I'm more often interested in only what I need to participate in. Show us that please!
I just took the time to watch through the whole video, and it does seem you provide quite a lot of features to handle these complex cases. I still miss the focus on "this is how you solve your problems" versus "this is the features of sprint.ly".
As for #3 in your list, we offer a feature where coder A can say, "Hey, coder B, you're item X is blocking my item Y!" When coder B finishes item X, coder A is alerted via email that coder B has unblocked them.