One for the fans, and easily the most subtle reference/easter egg in the game; Geralt's 'secret' tattoo. Triggered only by you carrying a save over from the second game and keeping a tattoo Geralt ends up with following a heavy drinking session with some Temerian soldiers in the 'Hung Over' quest, it'll then appear in Wild Hunt's opening sequence. Quite possibly the most brilliant easter egg ever put into a game purely down to how it relates so specifically to the Witcher fanbase, it solidifies CD Projekt as one of the most on-point and fan-pleasing developers around. Seriously, which other devs would think to carry this sort of thing forward?