The thing which actually annoys me the most on the 3ds version (not sure if it exists on other versions) is the frame drops. Normally this isn't a problem, but one example; I remember fighting the one boss in particular (the 3 headed thing at the bottom of the lift) which you're supposed to parry its attacks when it strikes. By the time you go to parry, so many frames have dropped that it's hard to judge, when it uses unblockable attacks you barely see the flash prior to the attack for the same reasons. You wind up getting cheap-shotted and the fact the camera pans out so far
you can't really see what is happening (on the 3ds version anyway).
I don't care whether it's 2d or 3d or 2.5d but the camera shouldn't be panning in and out because the game operates in 2 dimensions, yet the camera behaves like the boss is in 3d. Why? Also as was mentioned this may have been fixed in the HD, but stand still and you notice the camera moves and shakes or staggers... Why? Was it that hard to make a stationary camera?
I'm so guilty of whaling on MOF, in truth I score the game 49%. 33% of the game (Trevor's campaign) seems like it had more effort put into it than the entire game I score than portion 8/10 = 26.6%. Trevor was the only character who had a personality, which made me want to play his game more so than other others.
The rest of the game was less than half arsed and I'd say I enjoyed 1/3 of Simon's campaign (33.33%) and 1/3 of Alucard's campaign (33.33%) i.e. 26.66 + 11.11 + 11.11 = 48.88%