It's not perfect, but it's an addictive game you'll want to finish from beginning to end.
Each entry to the series introduced a new mechanic to enhance gameplay. But this time, Capcom chose to create an entirely new character. Despite their similarities (they even look the same), what makes the new protagonist, Nero, stand out from Dante is his right arm, the Devil Bringer. His entire fighting style in center around it, and although it doesn't seem all that amazing, you'll find yourself using it a lot for your amusement. In many ways, the introduction to the Devil Bringer breathes a lot of new life into a somewhat aging fighting engine by tossing in new strategies for each enemy and boss by rewarding you with a badass cinematic combos when you successfully beat down the various demonic presences scattered throughout.
Capcom also pulled a fast one by portraying Dante as the antagonist this time around. It's apparently quite obvious after the first mission that Nero, the hero, is not fond of Dante, as he is bent on tracking him down and killing him after witnessing the assassination of the leader of the Order by the hands of the Devil Hunter. It soon becomes apparent that Nero is fighting for his life and, ultimately, fighting to save his sweetheart, Kyrie. While the storyline isn't anything particularly original, the production value is above the roof. One thing that I, as a fan of both Devil May Cry and the Metal Gear Solid series, I prayed to God that Nero didn't end up like Raiden in MGS2. Thankfully, Nero has [almost] none of Raiden's personality, and he's [mostly] a semi-tortured character you can sympathize with.
As far as graphics go, DMC4 is definitely an eye-opener. Capcom has shown time and time again that they can utilize any system they work on, and they definitely proved they can work on the PS3 and 360 to full benefit (having played it on both systems, they're remarkably similar I couldn't tell the difference). Hook it up to an HD display and you've gotten yourself one of the best visual experiences to date. The environment is nicely detailed, as are the characters and enemies, but the biggest award goes to the bosses, which are large in scale and menacing to behold. One boss in particular is uses the power of the dark and cold, and while it may not be anything special gameplay-wise, it's cool to be able to see the system's lighting effects used very well here.
Speaking of gameplay, beyond the use of the Devil Bringer and a few tweaked enhancements, not much has really changed here. If you've played any of the previous Devil May Cry games, you should have no problem getting into this game. Most of the improvements are good, especially now that there are two different types of "currency" in the game: Proud Souls and Red Orbs. Unlike Red Orbs, which you collect by defeating enemies, Proud Souls are rewarded at the end of each mission, and the amount depends on your overall rating. The Red Orbs can be used to buy items, while the Proud Souls can now be used to upgrade your abilities.
While you do as Nero, you play as Dante is a small portion of the game, and while readjusting after you've gotten very comfortable using Nero may seem like a pain, you'll realize that Dante has turned into an even better badass. You certainly remember how fast Dante was in Dante's Awakening? Well in this one, he's INSANE.
My biggest complaint with the game is the backtracking. Sure there's bound to be backtracking in Devil May Cry games; there always has been. But this one takes it a bit far. I won't want to spoil anything for you, so you'll just have to see what I mean when you play it.
While Devil May Cry 4 definitely is one of the best looking games to come out thus far, whether it is better than the third game is still up for debate. It's not perfect, but it's an addictive game you'll want to finish from beginning to end because each combo and goal completed gives you a rewarding feeling, and when it's all said and done, you might just pick up that case again and pull the game disc out just to play it for kicks.