Four years on, RE4 is still a tour de force.
I'm an extreme latecomer to Resident Evil 4, having never owned a GameCube and never getting around to the PS2 version until recently. All I can say is, I wish I played this game sooner. It's unreal both how good this game is in terms of level design, action sequences and combat, but how heavily mimicked this game is. More recent blockbusters like Dead Space, Gears of War and Metal Gear Solid 4 pick up so much of what was done perfectly here in this game, which is perhaps the highest compliment you can pay RE4.
I guess the most important question for RE4 is: Is this game still worth playing here in 2009? And the answer is: Absolutely.
Technology may go out of date, but great game design (like great writing) lasts forever. Resident Evil 4 is a terrifically paced action-adventure that offers a substantive 20+ hour single-player campaign with incentives to replay, as well as two additional episodes that explore Ada Wong in greater detail. While the overall plot is a bit uninspired with plenty of groan-worthy dialogue, the ridiculously fun gunplay and excellent boss sequences more than make up for it. This is a game that maintains momentum even without an excellent storyline that pushes you forward.
I'm usually a story-first guy, but RE4 knows how to dangle carrots in front of you like nobody's business. You'll look forward to the combat sequences, the light puzzles and creative boss battles. You'll enjoy running all over the place looking for extra bits of treasure to sell to the frequent merchants and figure out how you want to augment your weapons as you move forward. The difficulty also scales perfectly -- just hard enough to keep you engaged and make you earn your progress. RE4 is a perfect example of how a game can make you feel proud of your ah-ha moments after you figure out a particular boss or puzzle pattern, but never so frustratingly hard that you give up in disgust.
In short, RE4 does all the little things you want in a video game right. There are certainly other action games and RPGs that might offer a more thought-provoking storyline, but very few rival the sheer joy in gameplay and pacing that RE4 has delivered so well.