I'm guessing you're asking if it works for games that have in-app purchases? The answer is yes. But if you're asking if you can get free in-game items that you usually have to purchase the answer is no. This method just gives you the app for free.
I've tested it on 5, 6, 7 and 8 and it works on all 3. I've also had this method approved by @Chloe although she didn't test it directly, I've told her how the method works and shes OK with it.
If for any reason the method doesn't work then I would simply refund you, however the method is only...