Pretty good. Worthy of 3 stairs and a half.
The art was a little iffy. In some places, it looked really good, but in others, such as pretty much every drawing of Ash, it didn't look that great. The backgrounds like the bushes / tree in the very beginning were bland. I know it's a cartoon, but each bush-bump looked exactly the same. And the rocks in the wall of the cave's entrance looked odd. You might've been better without them. Not sure why Ash was smiling as he walked into the Zubat cave, either. Ash's shoe as he steps down to trigger the Pokemon battle looked pretty...meh, too.
I will say that the actual Pokemon battle setting looked cool! I HIGHLY recommend that you stray away from hand written looking fonts, though. That's -my- own personal tick. They just don't look good. But hey, if they float your boat, go ahead.
When Ash says "Pikachu, use thunderbolt", that whole little scene looks abd. Ash is too low on the screen and his arm and hand are drawn pretty stiff. It also looks like Ash is naked due to the lack of arm sleeve. Maybe I'm just weird.
Those are just a few things. Overall, the art could use some work. Kinda funny, though. It's definitely relatable (many times have I almost thrown my GameBoy on the ground due to a combination of a Zubat encounters and one last Pokemon with HP in the single digits). You've definitely got loads of potential. YOU CAN GO THE DISTANCE. YOU CAN GO THE WAY.