I'm not sure if it has a name but it's very inspired by the flash games of the early 2000s. It happens to be a style I can pull off very easily so my default for prototypes - Id say the thing that makes it work is just that it's cohesive and consistent more than anything! I just use the same few colours, same pen size, same way of joining tiles and it works. I've been surprised by how many people have called it out, as I was throwing it together very quickly, but thank you for saying such nice things about it!