My submission. Can't think of a name for it. You pilot a prototype weaponized hovercraft while also trying to defend your platform as the train transports you to the capital city. The rebel forces try to stop you in their jets and by firing missiles at you.

Destroy jets with your hovercraft, destroy missiles with the gun towers.

Controls:

While landed:
Arrow keys - Move target
Z - Fire
X - Take off

While flying:
Arrow keys - Move
Z - Fire
X - Land (while above landing pad)

Not finished:
-Many of the graphics
-Game over screen
-Missiles are a bit buggy to shoot down
-In-game controls explanation

My excuse is I had work. I wonder how much more amazing this would be had I been able to use the full 72 hours. :/