Most game design documents are either too vague or so long nobody reads them.
Most indie games don’t fail because they’re bad. They fail because the developer tried to make three games at once. I’ve done this myself.
One version of the game exists in your head. One version exists in your GDD, and one version is what you can actually build with your time, energy, and skill. Most people ignore the third one. That’s where things break.
What Overdesigning Really Looks Like?
Overdesigning doesn't mean "too many ideas", It means ideas without limits. You start adding systems before the core gameplay feels solid. You keep features because: “they might be useful later”. "You plan like a studio but develop like a solo dev". At that point, progress slows down and motivation drops. Not because the game is bad, but because it’s unfocused.
What Happened With Spore War?
While working on Spore War, I realized the game was trying to do too much. Combat systems, game story implementation, extra mechanics, all sounded good individually. Together, they just made development heavier. Some features didn’t even make sense in the gameplay. Some made balancing harder. Some existed only because I liked the idea, not because the game needed it.
The Rule I Follow Now
If the core gameplay isn’t fun on its own, nothing else matters. Movement, combat, enemies that’s the base. If a feature doesn’t clearly improve that, it’s optional and optional features are the first ones to go.