Purchasing previous installments, just like Heroes 6, makes sense because licensed versions include expansions and have better graphics and sound. If you have issues with the new game, just say so. Any post here relates to something else besides Heroes 6. For example, there's talk about Black Hole. Or about other game installments, which are also discussed on this forum. Previous game installments are directly related to Heroes 6, as without them, the continuation being discussed here wouldn't have been possible.