Way back at E3 2003, Capcom showed off beta gameplay for a Resident Evil sequel that looked wildly different from the first two games. Whereas the earlier Biohazard games were about zombies, this demo had ghosts, possessed dolls, and spooky castles alongside a leather-jacketed Leon. A lot of it was either cut or changed for Resident Evil 4, but the remake has at least brought back one jump scare that never made it into the original.
As spotted by Reddit user KingGerog, the jump scare from the 2003 beta involves a deer head that was mounted to a wall. In the beta (which has also been affectionately referred to as Resident Evil 3.5), Leon comes across a beheaded deer that screams and falls to the ground in a pool of blood before disappearing in a flash of light. This and other supernatural elements of the 2003 build were later cut so that jump scare never made it into Resident Evil 4.
But it is in the Resident Evil 4 remake--sort of. In another part of Salazar’s castle, Ashley is walking down a long hallway holding a lamp for light when she passes by several stuffed and mounted animal heads when a deer randomly falls to the ground, startling her. It doesn’t scream or gush blood, but it’s certainly a nod to the 2003 E3 demo.
As KingGerog notes, the Resident Evil 4 remake leans more into horror than the original RE4, so this easter egg helps solidify the idea of terror for longtime Resident Evil fans.
That's not the only easter egg to be found in the new Resident Evil 4. Luis has a greatly expanded role in the remake and even provides a new connection with the third game. In the final chapters of the remake, you'll come across Luis's lab where there are notes and photos that confirm he used to work for Umbrella Europe where he helped create the STARS-hunting Tyrant.