If you use some GPL code and then don't share your code, is there anyway they can find out?? This is about a turn-based strategy game btw if that matters.
You don't even know what you're talking about. Dynamic linking is one thing and easy to understand without needed ANY tools, any PE editor will tell you what it imports, or you could just look at it in a hex editor and find the same. Static linking causes the code to be inlined, and to identify it, you'll need to detect code pattern, which is non-trivial, but doable, that's what FLIRT does.