SpaceShip

Controls:
Arrows - move
X - shoot
Z - shield

This is a game made around value exchange concept.
Ship has limited energy supply. If you get hit, it loses some energy. This energy is also used to attack. To recharge, you must absorb enemy missles with your shield. Shield energy is also limited, however it recharges up to a certain value for its own. To recharge the shield you must shoot enemies.
There are 4 enemies in current version of the game. You encounter them in rounds. Each round contains more enemies with more health. You must destroy all foes to complete each round. After each round you can boost your Ship Energy, Shield Energy, or Bullet Damage.

It goes bullethell very quickly, but it's quite forgiving.
This game still needs some calibration in my opinion, so I'm open for feedback.