Resident Evil 4 not only reinvents the Resident Evil francise, but also changes what a Survival Horror can be.
For instance, Survival Horror games have always used some sort of fixed camera angle. RE4 completely ditches that for a 3rd person camera. This completely changes the way the game is played, and as a result, the game has become much more action orrientated. There tend to be much more enemie encounters, and not as much puzzle solving. The overall map here is very large, so there is much less backtracking. Another thing RE4 changes about the series, is now there is a merchant, in which you can purchase weapons and upgrades (Like firepower, reload speed, etc.) and sell any thing thats just taking up space in your inventory. There are quite a few weapons in RE4, including pistols, shotguns, magnums, rifles and so on. All of them are very fun fun to shoot, and as a result, the gunplay in RE4 can be quite entertaining. However, one thing RE4 does with the shooting, is make it so you can not move while aiming a weapon. This can make things tense, as you draw a bead on a sickle wielding foe's head, while sereval other enemies are coming at you from all sides. This brings me to the next aspect of Resident Evil's reinvention. The AI. In previous installments, your enemies were slow and dumb zombies, that wielded no weapons, couldn't jump, etc. Here, you foes make full use of the environment, work as a team, and can be very unsettling. The enemy design is truly an accomplishment in RE4, and further adds the otherall feel of the game. Another thing that does are the graphics. Wow. The texrures, the character models, the effects...Are all very well done, and give the game an incredible atmosphere. The sound in RE4 is also very well done. The music, voice acting, and sound effects are all incredible. The music is just one thing I have to point out. This is the stuff you'd expect from an A+ horror film, and adds an incredible amount of atmosphereic tension.
This is just simply an amazing game. If you own a PS2 or GameCube, do your self a favor and pick up Resident Evil 4, since it is truly one of the best games of the year.
-Robert