Actually, you'd be surprised at what you can do with RPG Maker XP. Along with the scripting system, the engine supports program extensions through the use of Windows API access. To be honest, I think using Flash would be more of a negative than a positive. Performance would suffer on older computers, where RPG Maker would run just fine. My old Dell L400 would love to say high to that. Plus, RPG Maker XP with the Pokémon Starter Kit facilitates development quite a bit by already having the core features done.
Anyway, can't wait to see more, Luka. Hope you come up with a name for the other dimension soon.