Oddly enough, the only other Verse I've had trouble getting the Combo Platinum on so far has been in Chapter 14, where you have to fight one each of the giant ice and fire guys (Urbane and Gravitas), then one of the giant axe guys from the first game spawns in (Beloved, I think). You can't taunt in the Umbran Mech, so it's pretty hard to link your combo together between the first and second waves of the fight, and getting Platinum basically comes down to what your Mech's auto-aim targets at the instant the Beloved spawns. If it decides to shoot him, you're fine, but if it decides to turn around and aim at nothing (as it did for me half a dozen times) it's back to the title menu for you :P
That Chapter was actually surprisingly irritating to Pure Platinum for me. I've been cherrypicking levels to PP so as to avoid Balder and friends for as long as possible (because I know I'm going to struggle against those guys), so I've been clearing up all the non-humanoid boss Chapters first. I thought 14 would be easy (just hold Punch over and over, right?), but those last two flying angel fights were a real exercise in patience waiting for all the scripted events to finish so I could get back to punch-shooting.
I've been really enjoying Pure Platinuming my way through Bayonetta 2, though. Despite having been a diehard Platinum fan and having played all their games, this is the first time I've felt enticed to do the whole Pure Platinum thing, and I've just been taking it one or two Chapters a night and having fun. There's nothing quite like the feeling of waiting nervously for that ranking screen to come up, hearing the three little whoosh noises and then Bayonetta saying "Baaaaad booooooy". One of those perfect video game sound feedback things; I feel like I'm developing a Pavlovian response to it already :P