ReShade 4.8.2

Older video games rarely hold up to modern standards in terms of graphics, understandably so. The textures are obviously incredibly out of date and the particle effects especially don't hold up. However, the main thing holding them back is the lack of post-processing effects. Things like cinematic shading or ambient occlusion goes incredibly far for the look of a game, enough that having them can make up for a game's rather lackluster textures. ReShade is a program that looks to inject that into every single game out there.

To install ReShade, simply run the installer and follow the instructions. You'll have to pay attention because it's more in-depth than most other programs.

The way this program works is that it acts as an injector, and gives almost every compatible game generic post-processing effects. This can sometimes mess with the game a bit too much because it's based off of detection and not handcrafted for each game. For example, in Final Fantasy XIV, a lot of the effects end up blurring the HUD, making it very difficult to keep playing the game with them on.

Nevertheless, this program is also shockingly effective at making each game look good despite its auto-detection. It can easily make even the oldest games look a little more like an Avant-grade modern game than a truly dated experience. 

If you want to make your games look good with not that much effort, then you should definitely give ReShade a download. It's a borderline miraculous piece of software.