Nice!
I watched the first video and I think it's good you use code in your tutorials from the very beginning,
since code is 'the power of GE'.
Anyway, I think you should have explained a little more about how the code works.
The basic maths behind the dir = key[KEY_RIGHT] - key[KEY_LEFT] -equation and how switch case works.
Also could have been good to tell that the // -parts are just comments that don't do anything but help understand the code.
Anyway, it's nice to see you making tutorial videos! These kind of videos helped me to begin with Game Editor.
EDIT:
Also watched parts of episodes 2 & 3, they are good.
However, I have to ask why you don't just use the 'player' actor itself for the collisions?
I'd recommend using another actor for collisions only when the whole player actor isn't supposed to be able to collide.
But if there's some reason, I'd be glad to know.
And I got to say I was very delighted to see you use sprintf for the score, this way new people learn to use it from the very beginning.
That textNumber isn't really a good option at all, so it's nice that you don't advise people to use it.
Keep up the great work!