Problems...
I downloaded the demo, but I seem to be having some problems.
First: Your into with Mew, Celebi, and Jirachi was awesome, but it had a good number of spelling errors. You'll probably want to fix those.
Second: The enter Hero name screen came up, and then I had my chat with Professor Oak. Then he made me give my name again. You might want to fix that.
Third: Additionally, Oaks speech is extremely short. Perhaps he should have a little more to say.
Fourth: Your maps are too large. Your room has too much blank space, and downstairs was WAY to sparsely furnished. Shrink the rooms and add some furnature. Oaks lab was too big as well.
Fifth: In Oaks lab, when you select a Pokemon, the ball it is in doesn't leave the table. Kinda wierd... Then your "brother?" appears (he was invisable for me, you seem to have selected the wrong part of Gary, cause all I could see of him was him with his fishing pole as he walked down), and takes a Pokemon which doesn't leave either. Again, Oak was too brief. More Dialogue would be nice.
Sixth: Back in town, some of the text boxes were funky. After I looked a building sign, the next character I talked to had that same box, which was different from all of the other characters. Professor Oaks door wouldn't open into his house. When I tried to enter the really big building, I wound up back in the Heros house.
Seventh: When I tried to leave town, my invisable rival appeared. He challenged me to a battle, which initiated, then crashed. It "referenced a script that does not exist."
That was as far as I currently am. I know it sounds like I'm trashing your demo, but I know how much effort you have put into this and I can tell you are working hard on it. These are just suggestions to make it the best it can be. I mean no offense. I'll try to get past your rival battle and play from there. I know the final product will be great!