It seems I'm late to the party, but I finally got to watch Pokemon The Origins.
I was nearly crying from all the nostalgia. The old save/load screen, the music, the whole journey and additional sidequests (such as getting the rods)... Everything just made me want to play the old Gen 1 games again.
The voice acting was splendid, and I was impressed with all the new animation - especially the battle effects. They certainly put a lot of effort into all those movements. Also, I like how they had Red narrate some of his journey so we wouldn't miss out too much :D I also liked how they had Red start out as a character who was only trying to fill the dex for Prof. Oak to someone who gradually matured into someone who understood pokemon and created a firm bond - hence, the Mega evo at the end felt more dramatic and made plenty of sense.
My favorite battle was Red vs Giovanni. The flashbacks were a nice addition, and I felt I could understand more about Giovanni's character. He was more than just a villain boss in this special.
If I were to give my personal ratings, I'd give it a 10/10. I couldn't ask for more :D I appreciate the time they took to develop this, and I loved it!