Spelunky procedurally-generates its levels, meaning you'll never ever play the same stage twice. But how does this magic actually work? How do you get to play through actual playable stages, and not nightmarish collages of terrain?
Darius Kazemi's "Spelunky Generator Lessons" explains that every level is made in two stages. First, there's the "solution path", which builds something that actually has an entrance, exit and (relatively) navigable terrain. The second adds the spikes, enemies and items.
Which makes it sound easy, but the guide breaks down why it's so special in Spelunky's case, how they did it and why it works so damn well. The best part is the fact that you can even interact with the guide, building your own levels with the press of a key.
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Spelunky Generator [Darius Kazemi]