This is an excellent game!
This game is not a mindless zombie killer, instead, it is a very thought-provoking posessed and cult people killer.
This game requires you to think. It challlenges you with puzzles and doesn't hand ammo out like candy. You are forced to preserve your ammo and thinking of other ways to dispatch the hoarde.
The storyline is as effective as can be, and very very unique, for one thing. I won't give away any details about the story, but trust me, it rocks.
The gameplay is good too. The buttons are in the perfect positions and overall it works out nicely. The difficulty level is such that you re both challenged but not overwhelmed, but remember, conserve your ammo, or you WILL have a tough time.
The boss battles are the highlights of the game (this is not to say the other parts were bad). They are F-U-N. They have a range from puzzling to fire rockets at will, and are the best you could ask for.
And who could possibly forget the most annoying aspect of the game? The escort. Yes, the escort. It follows you around with no means of defending itself, meaning that if one zombie is left behind, the escort becomes a major liability. This is a part of the game however, and furthur advances the storyline. If you get angry, do what I do. Run through a crowd of zombies and then watch them tear the escort apart...good times.
In conclusion, this is the best RE game to date. It's fun, challenging, and you can shoot people in the head. There is even a smooth talking mexican dude. Yes, a mexican dude.
I give Resident Evil 4, a 9 out of 10.