Not many developers let you control their games with your voice despite loads of games putting you in the position of a commander. Voice control would fit with that role nicely.
Celestia is one of the few. You take a young, isolated star and build it into a complex galaxy using only three different vocal tones.
“Celestia is a vocal interaction music game,” say the developers. “Incorporating visualization technique, Celestia uses voice input based on pitch detection as a primary means of control, and provides insight into innovation of vocal interaction.
“Users sing three pitches who are bound together to guide a newborn star through the universe with melody. In each phase, a new pitch is introduced.”
The first phase has you orbiting a sun. By singing deeply into the mic you can send out a gravity pulse that pulls in loose planets.
In phase 2 you weave your star between other galaxies, grabbing more planets as you go, singing the low note as before, but also singing in a higher note to dodge incoming comets.
In the final phase you do the same as in the first two phases but you now have a third even higher note to sing. That note jumps your star forwards, allowing you to suck in moons before they’re pulled into mega suns and destroyed.
The mechanics are simple and the game may not be “scientific” but it looks like a great concept for something larger. If the core was developed further, you could be flying through space singing tunes to create complex patterns of action on the screen. Altering gravitational pull to hug your planets closer or ease them away, saving them from passing comets or asteroid belts. If the whole thing were choreographed/scored well then you could be quite tuneful when the whole thing was done. Like a singing guitar hero space opera.
You can read more about Celestia on its website.