Added an option to enable or disable planetary gravity for the player (if you find it difficult, you can turn this mechanic off).
Fixed loading/saving of artifacts in the bonus level (unfortunately, if your artifacts disappeared, you will have to start over).
Added protection against FPS drops in the bonus level during explosions.
Added translations for artifacts.
Fixed translations in some areas.
Known issues:
The Infinite Tunnel is not truly infinite — after around 120 units, the ground stops appearing (although the tunnel itself continues).