I've spent a bit more time now trying to figure out the best way to animate my characters, but now I've got a bit more energy to properly evaluate the project, it's becoming pretty clear that once again I've dragged myself way off the original plan. "Project Jack" was orginally meant to be a simple dungeon hack 'n slash that I could throw together in a few months to get my feet wet on a small but complete game project, but during the recent period of dray-dreaming and sketching during periods of procrastination during my paper write-up, it's morphed into a platform action-adventure epic about a band of heroic mouse-creatures. Admittedly, I like the new game concept, but for this first prototype game I'd prefer to stick to something that can be described more often with the word "simple" rather than "epic", and which I might have a chance of complete in the next two years.
So now I'm strongly thinking of going back to the original plan of making "Project Jack" a Rogue-like Gauntlet/Zelda-esque game, where the hero is just a mop-haired vehicle for swinging a sword, and the game story is merely "Fight stuff, avoid traps, collect loot". This way I can focus on making the project what it was meant to be, and I won't mind so much if I make a complete pig's breakfast of the internals because it's a learning experience.
Meanwhile I think I'll write up a few game design documents for other potential projects, such as the mouse one, to figure out which ideas catch my fancy (and to get experience in document writing and more concept art, of course).
Quick question: in your opinion, what's the best tool to use for writing game design documents? At present, I only really use LaTeX for large documents, which is great for automatic sectioning but not so good for transposing artwork within the text (other than as figures). Do you think including lots of diagrams and pictures within the text is a useful thing when writing up designs?