I watched this one with not ever seen a Pokemon movie, series or special. So now that I have finished it, I can say it was a good watch. It had a straight forward plot and later I found out was a mash up origin movie or sorts. Even with it being an origin story though I did like how the story moved along and finished.
Animation was good, very nice battles scenes and when it came to mood changes, it was shown very well in dark and light tones and/or shadowing for those particular moods. Sound was great. In story music was very crisp and clear, the opening and ending themes were good as well. Now I can see how the Pokemon songs can be catchy.
Characters were ok. I gave it a half rating because there wasn't enough background I thought on Ash's friends. Even if this wasn't a full origin movie I would have still liked to know who he was traveling with. So think more background info would've been good.
Overall I did like watching this, even if I don't see another Pokemon anime, I still think this is a good one to watch.