Here is my game for the LD38.
A busy week-end, so I just made the core Gameplay of the idea.
Invaders attack your little planet. They dig into it to destroy its core.
How To Play :
Use arrow keys to move the defender (green guy).
Use space to jump.
Use the action button (Left Ctrl) to unearth the percer things.
Touch the blue parts to kill en ennemy.