Devil May Cry 4. I loved 1 and 3 and was excited to hear about DMC4, I haven't played much of 2 but it wasn't bad from what I did, but I really couldn't get into 4. I lost my save data the first time I got to Dante, and the second time I played I felt so uninterested I just set it to easy, trudged through until I got to play as Dante and then haven't played since. If I were to go back to 3 or even 1 I could probably play them, enjoy, and beat them again, it's not the formula getting old, nor was it even Nero, hell I like Johnny Yong Bosch as a voice actor, a great deal, my only problem is he sounds so samey with his voice, but that's another topic. Perhaps 4 just lost the spark, but getting through the game halfway both times to the point where I get to play as Dante and not want to continue? I dunno, you'd think playing as Dante would make you want to continue, but I hear it's just the same levels backwards and it just feels cheap.
TL;DR, Devil May Cry 4.
TL;DR, Devil May Cry 4.