Okay, I can get the aspect ratio thing. That sounds pretty troublesome! (Maybe an easy solution is to force drawing two black rectangles in the appropriate areas? In any case, future feature!)
I've started actually developing a full game now, and it will specifically target and use minisphere functions whenever appropriate. I'm sure I'll be using the debugger too. I probably won't encounter many problems while this RC is happening, but at the very least there'll probably be feedback I can give you at a later stage. 
Edit: tried creating an s2gm file according to the API documentation, but I'm getting an error when trying to run the game:
minisphere was unable to load the game manifest or it was not found. Check to make sure the directory above exists and contains a valid Sphere game.
My s2gm looks like this, which I'm guessing is probably out of date? It's directly copied and modified from minisphere-api.txt...
{
name: "A Game",
author: "DaVince & SarahB",
summary: "Our description goes here",
resolution: '1280x1024',
script: 'scripts/main.js',
minimumPlatform: {
recommend: "minisphere 3.0 or later",
apiVersion: 3.0,
extensions: [
"sphere-legacy-api", //By the way, do I need these?
"sphere-obj-constructors",
"sphere-obj-props",
"sphere-map-engine",
"sphere-rng-object",
"sphere-s2gm",
"sphere-spherefs",
]
}
}