Resident Evil 4 is back. For the 4th time. Originally released on the GameCube, then ported to the PlayStation 2 and PC, the question that most Wii owners will be asking themselves is not Should I buy Resident Evil 4? but Why should I buy Resident Evil 4 again? Read on for a brief overview of the games predecessors, so that newcomers can appreciate just how groundbreaking Resident Evil 4 was when it was first released, and then continue for a detailed comparison of every version of it, so that you can decide if the additions to the Wii Edition make it worth buying again - or which one to buy in the first place. And yes, I did (rather sadly) actually bother playing through every version of the game to write the comparison. Anyway, Resident Evil has the distinction of being the longest running Survival Horror series of videogames, and is often credited with creating the genre in the first place. This is a point of great contention amongst videogame historians, because unlike most genres, Survival Horror is defined by its themes as opposed to what it requires you to do, making it hard to choose just which games fall into the category. For instance, you can be pretty sure that a Racing game will require you to, um, race. So its pretty easy to tell which games are Racing games. But what of Survival Horror? Just how much survival must take place, and how horrifying does it have to be? The short answer is that there is no answer, so unless a developer announces that their game belongs to the Survival Horror school, theres no sure way of knowing.