Complex sentence: Slender Man will not stop chasing the player's character even if all the eight pages have been collected, though the end credits can be viewed if all 8 pages were successfully collected, and new game modes are then unlocked.
Split into simpler sentences: Slender Man will not stop chasing the player's character even if all the eight pages have been collected. However the end credits can be viewed afterwards if all 8 pages were successfully collected, and new game modes are then unlocked.