Great talk and very easy to follow, even for those of us who have not been exposed to functional programming that much.
The one thing that I would comment on is that the speaker kept looking at his notes if he forgot something. Seeing as he talked very naturally about everything, this seemed unnecessary and gave the false illusion that the speaker was very unprepared. Next time, just trust that you know what you're talking about and just go from there :)
The speaker was very relaxed and had a nice way of talking. Pace was also good, the talk was easy to follow.
One thing that could've been better is that the speaker should have practiced a little bit more beforehand regarding how long the talk would take. He already started the talk saying he wouldn't know whether he would have time for the last section of the talk. The talk could have been arranged such that everything could have fit in, by simplifying or omitting details in the beginning of the talk, which would have made talk more round, and not leave an open end such as it was today. Not that it really bothered me, the rest of the talk made up for the lack of the last bit, but it somehow it didn't feel quite finished.
Also, the speaker kept saying "I'll come back to this later" quite a lot. Normally this would indicate that a talk is not structured all that well, but in my opinion that was not the case here. The structure was fine, and it felt natural to come back to some points later in the talk, however, the fact that the speaker kept drawing explicit attention to this made it feel a bit weird. Keeping the presentation the same but saying "I'll come back to this later" less often would improve this talk.
(wow, it looks like with the "new" version of Joind.in I must have an account to post? Last thing I need is Yet Another Account)
In general I liked this talk, the topic was sooo interesting. However it can't hurt in the future to talk a bit louder, the mike seemed to be just for the camera.
I do wish, as Remon mentioned, that the talk pace could have been restructured so that the final part could be included-- as seen by the questions and interest shown at the end. After all, it's the concurrency that's the New Hotness for many developers, even ones who've been doing functional programming in other languages, so seeing in more detail how for example Phoenix worked with it would have been a blast.
Slides were super clear and readable, even with my bad eyes. Nice