[Deestan]

> if you need some settings that can be accessed/changed from many different classes then the design of your app is severely lacking.

If he's making a game, this is completely acceptable design. Games programming is wildly different from application or server programming. Also, strict TDD is much, much less useful in games programming than anywhere else. Writing unit tests for central data structures and algorithms is useful, of course, but the majority of modules/classes/objects are so small, uncritical, and change completely so often that it's not worth bothering.