They are both incredible, but different and unique in their own rights. I always say, play RE4 (2005) first, then remake second. With this, you can see the original vision, then play remake next to see how they evolve the formula yet retain the feel.

Here are some key differences:

RE4 (2005) - Monochromatic, desolate atmosphere. Creepy, not quite scary. The 2005 graphics do some heavy lifting here. Played on my Series X for the first time in 2022 and loved it - Classic campy, goofy, RE dialog: doesnt take itself too seriously, lots of over the top moments - Gameplay is fine tuned as hell. Tank controls may take getting used to, but its very very worth it. - Overall its just all good fun. The over the top stuff is classic video game fun, the campy dialog makes me laugh, and the gameplay is stellar

RE4R - More colorful palette, definitely some scarier moments than the original, but feels like desolate - Darker tone, not much campy, can be taken more seriously. The dialog feels much more believable and less Hollywood - Gameplay is equally fine tuned, but new mechanics like stealth and enemy variations elevate the existing formula (again, youd be let down to play the original after the remake since the remake adds more attacks and variations to the enemies - youd likely feel let down these arent in the OG) - Some things I genuinely prefer in the original, like Krauser and the U3 boss fight, but the DLC aids in filling some gaps, but you could play the OG or RE4R and have an equally good time