Dark Boson X is a free level pack introduced in an update to Boson X, including 6 new particles to discover (all just "dark" versions, but completely different than the first 6, including new gimmicks to the levels.)

These experiments are:

  • Dark Geon
  • Dark Acceleron
  • Dark Radion
  • Dark Graviton
  • Dark Y Boson
  • Dark X Boson