Imagesource: https://lethalguitar.wordpress.com/

Parallax scrolling can be considered an old hat. But back in the days when 2D platformers were the predominant genre, this technique was considered real eye candy.

Depending on the target platform hardware features could be used for the implementation. But on a PC parallax scrolling remained kind of a rarity. Background: An implementation of different scrolling speeds of background and foreground layers in realtime was nothing that would have been easy to implement, even at the beginning of the 90s. 

Nikolai Wuttke-Hohendorf aka lethal guitar recently approached the topic, and picked one of the best examples: Duke Nukem II.

In his article he sheds light on the underlying technology in detail - which is more than interesting. Especially implementations on some virtual game consoles (no name dropping here) could certainly benefit from the basic ideas.

But also beyond that his post is more than interesting reading material.