How Spelunky's designer set out to create complexity with simplicity

- Spelunky creator Derek Yu dives into how different elements of the game interact with each other.

For the latest video in its ongoing documentary series, Noclip sat down with the creators of the procedurally generated platformer Spelunky to find out how the game came to be and exactly what makes it tick.

The first half of the hour-long documentary above explores how Derek Yu and Andy Hull got their start making games with Klik & Play and even, in the case of Yu, running the indie game community TIGSource.

But the second half of the documentary should be especially interesting to other developers since it runs through the design decisions powering many of Spleunky’s individual elements and talks about how the game sets out to create complexity through simplicity. 

“We're trying to draw out the personality of each area, of each monster, just from very very simple actions and things that they do,” says Yu. “And when they all come together, you get this complexity that's very interesting and that makes every time you play in this randomized environment fun."

He uses some enemies in Spelunky’s second stage, a jungle, as an example of this complexity in action. Among the enemies in that area are leaping frogs, swimming piranhas, and monkeys that cling to the player. On their own, these obstacles are fairly straightforward but when Spelunky’s randomly generated floorplans cause these enemies to overlap, new challenges spring forth.

The full interview takes a look at how individual items, mechanics, and enemies were designed to create this kind of emergent gameplay, and also offers a look at how the developers use in-game death as a teaching tool rather than a punishment. For other videos like this, be sure to take a look at the Noclip YouTube channel for documentaries about Doom, Rocket League, and more.