How would I create this effect in Photoshop/Illustrator?

I would look on Google but I’m not really sure what to look for as I can’t seem to get any decent tutorials from my searches… (how would you describe this effect?)

I like the art style (not the vector graphics but their textures) of the flash game Icycle and want to replicate it/experiment with it in Photoshop or Illustrator (preferably Illustrator). I don’t mean to explicitly rip the artist’s style off so much as learn how to create such an effect and then produce my own unique spin on it and so forth. It seems like a pretty common effect in vector art but I can’t seem to find any resources on it… maybe I’m just being stupid with my searches.

Here’s an example.

Any resources, tips, or effects I could use to replicate this style?