This game is amazing. I have just finished Beta 0.3 (well, I am inside the helicopter, being attacked by Pikachu, and when I exit it I appear in Lavender Town Pokémon Center, so I suppose that's it). It's such an original game, it's so fun to steal Pokémon, items, etc. I loved getting Slowpoke and Smoochum that way (and I was also lucky with Smoochum's Modest Nature). Now they are great Jynx and Slowking. Congratulations on making a great game, I really look forward to future releases.
The only thing I don't like is that starters (in my case Koffing + Meowth) are too weak. I had to stop training Koffing at lv 14, because it didn't do any damage, and had problems with everything. And I stopped training Meowth at lv 23, because it is so weak, it cannot win any single battle, after finishing the Mt. Moon quest, it always dies because it is so frail, and lacks offensive power, Fake Out is the only thing it has going for it... (perhaps you should increase their stats, or if you already have, maybe a bit more?)
There is also a problem with the items trainers use, such as the X Items. They can be useful and make things harder, of course, but normally it made me things much easier instead, especially in the Pokémon Tower in Lavender Town. Haunter/Gengar are frail, and when using the X Special item I can just KO them in two hits being hit only once.
Apart from that I found a few bugs, and I took screens of 2 of them:
Zen Headbutt should be a Psychic-type move.
Here, Ledyba is mentioned twice, and in the second one it should be Spinarak.
Also, the elemental fangs are broken. The 3 of them have 100% of inflicting Burn, Freeze, or Paralysis, respectively.
I also wanted to ask you something. I evolved my Growlithe quite early, level 23-25 if I recall correctly. Have I missed any important moves, or will Arcanine be capable of learning useful moves in the future?
Thanks for this great game, it's one of the best hacks I've seen.