A huge amount of recycling in DMC4 is its only flaw :(
The game shines in terms of its graphics and HD, well acted cutscenes. The story line plot is good.
The major flaws of DMC4 is that you play the game from beginning to middle (around chapter 10) as the new hero "Nero". Up to here, there is very little to fault with the game.
However from chapter 11, just when you've about got used to Nero...the game forces you to play as dante from which point you will have to learn a complete and very different set of skills and combo moves.
The biggest disappointment is that the the game recycles itself. When you play as Dante, you bascially replay the game again but this time from the end to the beginning going via all the bosses you've met before in the game in the reverse order! The in Chapter 20 you fight them all again! Three times in the same game! Talk about recycling :p
Bonuses seem pretty average and very hard/ very tedious, so i doubt i will be spending hours trying to complete them all again just to collect 4 blue crystals to boost my health.
Overall, a good buy, good hack n slash with good combos moves- the designers obviously cheated DMC fans by recycling the game. Easier than DMC3.