It was pretty obvious what was going to happen when he said he has no pokemon.
But although I waited in vain for a punchline, this was an entertaining short animation.
I can see now why Professor Oak did not let Red enter the tall grass without any Pokémon :D
Was it intentional to use the Route 1 theme to indicate that Ash is at the very beginning of his journey?
Or did this even occur before he got his Pikachu?
Or did you simply take it because most people recognize it? (Then again, that's true for pretty much any soundtrack from generation 1.)
Everybody knows Pikachu is Ash's always present sidekick, so - unless my above theory is correct :P - it was weird to not have him around.
For that reason i would probably have replaced him for another trainer in your animation - even though there's basically no Pokémon trainer out there without Pokémon in the first place.
Or maybe you could have chosen a character that's not a trainer (that for some reason still felt like catching a Pinsir)?
This probably would have resulted in a less mainstream-appealing title, though...
Now let's put the story and its interpretations aside and get to the movie quality:
Both voice acting and animation were really good, and the sound effects (using both known ones from the movie and the games) were nice, too!
So overall, good job!