游戏说明：

游戏控制

WASD or Arrows: Move your ship.
Left Mouse: Fire at enemy ships.
Space Key: Fire your ultimate weapon, clearing out all enemies in your current timeline.

Pick up crystals to charge your ultimate weapon.

It is possible to shoot through the portal, hitting enemies on the other side.

Watch out for enemies wandering out of the portal.

Try to avoid leading enemies into the portal. Chasing after them into the other timeline only makes things harder.