How to Darken Brown Shoes that aren't made of leather

I searched and searched the internet trying to find advice on how to darken brown leather shoes but could only find advice for leather shoes. These shoes are not leather. Since I have a solution, here it is, internet.

First of all, I bought these shoes for my DragonCon steampunk owl outfit. They were on sale and I like them, but they were more tan than brown and I wanted them darker. So I removed the laces and got a tin of brown Kiwi shoe polish.

I didn't use any kind of fancy shoe cloth, just a paper towel. It worked just fine. I spread a layer on the "leather" parts of the shoe (I think they're polyester) and was pleased that it acted just like leather. The polish soaked into the grain and darkened immediately.

I did two coats, then did the other shoe. The lighting in this picture isn't great, but hopefully you can see the difference in the darker rear shoe and the lighter fore shoe that I hadn't yet worked on. They darkened a bit more overnight too, I guess as the polish soaked in more.

The next day I took a clean paper towel and buffed the shoes. I was worried the polish would come right off again, but it didn't. It just buffed to a nice shine. I replaced the laces with darker brown and threaded a fake key on one to see how I like it (I don't; I'll probably replace it with something else eventually). I was going to glue something to the shoes themselves to make them more steampunk, but so far I haven't found anything that I like well enough. But I think they look good as they are.

They're going to kill my feet, but I'll look stylish.