Don't square things up. Space the trees out a bit and make them look a bit more natural.
Mapping is unusual. Try not to map trees in a straight line- it's un-natural.
I think that's why it's catagorized in 'Other'.
Apparently you are not creating a 'Serious' RPG, something that isn't so cartoony and mixed up. If you are, I wouldn't recommend characters from other games.
The first thing I personally would do is think about the game's size. Is it going to be massive, or is it going to be small...? Then, I move on to the genre of the game. After that, the most usual thing is to create a prologue backstory, then write a story from that. That's basically iamnot's idea, but thinking about Size first. Then I wander to exploration, what I want the player to see in the game, enter dungeons, towns, forests, and whatnot.
Guardia Castle...? Does that help?
What's with the wacked out title..? "FUTAGONOKAMISAMA II"
Looks like a very good side-scroller. I hope more of your games turn out like this.
Quintessence has been on my top 10 list for RMXP games for a while now. Downloading as well, I'll update this post when I'm done (which won't be for a while).