Yeah checking urls is the go to method.
Of course that's complicated if the host uses a content delivery service, which creates random urls, and pretty much any automated service will have to use them.
There are other methods which probably shouldn't be discussed publically, as that leads to those methods being bypassed.
One method that should be ok to discuss is just a Google search. It does them no good just to mirror your work, they need to advertise it just like you do.
I would note that even though the game was taken down, the reference they give to the spiders was never removed, and is actually the first return from a search.
I realise that they are just shitty little games, but for a first real try at self publishing, it was not a pleasant experience.