In regards to ICDX being demoted, it was dropped to Insane Demon difficulty practically at the very beginning of 2.2's release. Bear in mind, that the update introduced revamped physics and FPS count no longer influenced ship's movement behavior, meaning that players with 60hz monitors generally experienced the same ship gameplay as people who owned monitors with much higher refresh rates. ICDX, being a level with plenty of tough flight sections, got indirectly nerfed due to that. Even before 2.2's drop ICDX's difficulty was a topic of heated discussions, but a lot of people generally agreed at the time that new ship physics made the level much easier compared to how it was before the update.