Resident Evil 4 is an amazing game. There is really nothing wrong with it. The boss battles are intense, and even the Tier 5 (crappiest) zombies can be difficult. Aside from that, you can shake enemies off and backflip out of their grasp. Also, zombies have hit zones. If you're fighting three, you can shoot two in the legs and they will fall and take time to get back up. Sometimes you can get penalyzed for shooting zombies heads off (I won't spoil anything). There are interactive fight scenes and FMV's, where if you don't press a button fast enough, you'll die. It is also more realistic in dying too. A zombie bite might only scathe the skin, but if you meet those huge guys that look like Baraka from MK, then they can easily swipe off your head with a single blow.
PLAY THIS GAME NOW. THERES NO EXCUSE, ITS COMING FOR PS2 NOW ALSO.