I can't say it enough... the drops to 30fps during boss fights is my issue and I'm not happy.
Just to give you a heads up, the first level is definitely the worst I've encountered so far. Dips to 30 don't usually happen during gameplay, but they happen quite frequently during camera transition things, like when you're done talking to an NPC and the camera pulls back to gameplay; the game dips to 30 for a few frames.
It was
bad in that first world for someone sensitive to drops like me, though dips very rarely happened during gameplay. Still, it was enough that I stopped playing, felt disappointed, and bitched about it in this thread last night. (Rightfully so!)
But the good news is that once you get past that first world, the game runs waaaaaaay better. You'll still get an occasional frame or two that'll drop during one-off transitions, but I only noticed like 2 or 3 over the course of hours of playing. Pulling up the map can still pretty consistently get frame drops no matter what level you're on, but it's not during gameplay, and it doesn't really matter when just looking at the map.
I really hope Nintendo can optimize that first world, because it left a bad first impression on me, and I imagine for a lot of other people sensitive to drops. But, so far, the rest of the game is much, much smoother.
I have no doubt I'll hit a few upsetting bottleneck levels or boss fights later on, and that will genuinely suck. But since it truly seems like 99% of the game runs excellently, I'm not gonna throw the baby out with the bathwater.
Especially because this game
fucks. It's so insanely fun.